CALGreen · California Green Building Standards Code (CALGreen)
How should site grading, drainage and surface water be managed?
CALGreen requires your construction plans to show how site grading and drainage will keep all surface water away from buildings (examples: swales, French drains, retention gardens). If the work doesn’t change the drainage path, the exception applies; otherwise show the routing, measures, and any overflow paths so the enforcing agency can confirm the building will remain dry.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
Construction plans must show how the site grading or drainage system will manage all surface water flows so water is kept from entering buildings. This is the mandatory CALGreen requirement in § 4.106.3.
Keep surface water away from buildings: your construction drawings must show the measures (swales, collection/disposal systems, French drains, water‑retention gardens, etc.) that will route or retain runoff so it does not enter the structure. (Plain‑English restatement of § 4.106.3.)
Requirements in detail
Core obligation
- The single enforceable obligation is that construction plans must indicate how surface water will be managed to prevent entry into buildings — § 4.106.3.
- The code lists example methods (not an exclusive list): Swales, Water collection and disposal systems, French drains, Water retention gardens, and other water measures that keep water away from buildings and aid groundwater recharge. § 4.106.3 provides these examples.
What plans need to show (practical items to include)
When the plans indicate how surface water will be managed, typical items the enforcing agency will expect to see are:
- Location and type of measure(s) (e.g., swale, french drain, retention garden).
- Flow paths showing where runoff from roofs, driveways and yards will go.
- Connections to public drains or on‑site disposal/retention features (if any).
- Any filtering or barrier systems used where runoff enters public drainage (see construction‑stage requirements in § 4.106.2 for on‑site filtration during construction).
- If the project is an addition/alteration that does not change the drainage path, the Exception in § 4.106.3 applies (no new plan requirement for altered drainage).
Decision table — choosing measures and what plans must capture
| Typical measure | When to use / function | Decision‑relevant design notes (what to show on plans) | Code Reference |
|---|---|---|---|
| Swale | Convey overland flow away from foundation; useful for linear routing along lot edges | Swale alignment, slope, outlet location, erosion protection, and any down‑drains | § 4.106.3 |
| Water collection & disposal system (roof leaders → tank/pipe → discharge) | When routing roof and hardscape runoff to a storm sewer or on‑site infiltration system | Inlet locations, pipe sizes/routing, discharge point, and overflow/path for storms | § 4.106.3 |
| French drain / perimeter drain | Keep subsurface and concentrated surface flows away from foundation | Trench location, pipe invert elevations, filter fabric, and outlet detail | § 4.106.3 |
| Water retention garden (bioretention, rain garden) | Slow and infiltrate runoff; adds groundwater recharge and treatment | Planting plan, below‑grade media (if any), overflow route for large storms | § 4.106.3 |
| Other measures (retention basin, diversions, recharge features) | When on‑site retention or recharge is required or desired | Storage volume, outlet/rill details, and demonstrated overflow protection | § 4.106.3 |
Notes:
- The table entries are practical plan content items consistent with the examples listed in § 4.106.3; the section itself does not prescribe detailed dimensions or volumes — it requires that the plans indicate how surface water will be managed.
- For construction‑phase stormwater controls (projects disturbing soil), see § 4.106.2 (retention basins, filter barriers, compliance with ordinances).
Exceptions & special cases
- Exception in § 4.106.3: Additions and alterations not altering the drainage path are excepted from the requirement to show new grading/drainage measures. If the work does not change the drainage path, you do not need to supply new drainage measures on plans.
- Construction‑stage rule: projects disturbing less than one acre (and not part of a larger plan that totals ≥ one acre) must manage storm water during construction using one or more measures noted in § 4.106.2; larger projects are subject to State Water Boards requirements (referenced in § 4.106.2).
If your site is subject to a local stormwater ordinance, complying with that ordinance is an acceptable method for construction‑period drainage control per § 4.106.2.
Common mistakes
- Submitting plans that simply state “grading will divert water” without showing how (location, outlets, flow paths) — the code requires the plan to indicate the measures, not just state intent (§ 4.106.3).
- Omitting how roof leaders and downspouts are handled (e.g., draining to an impervious area adjacent to foundation) — plans must show where all surface water flows end up. § 4.106.3.
- Treating CALGreen as only a recommendation — § 4.106.3 is a mandatory plan requirement for covered projects.
- Neglecting construction‑phase controls for sites disturbing soil: even small projects (<1 acre) must implement measures in § 4.106.2 during construction.
- Assuming the listed measures are exhaustive: the code gives examples; other effective measures that keep surface water away from buildings and aid recharge are acceptable if documented on the plans (§ 4.106.3).
Worked example — concrete scenario applying the rule (with numbers)
Scenario: New single‑family house, roof area 2,000 ft², lot slopes toward the south side where the driveway and a planting strip exist. You must show how surface water is kept from entering the foundation.
Plan items to include to satisfy § 4.106.3:
- Indicate measure(s): propose a swale along the south lot line and a water retention garden at the south corner to capture driveway and roof runoff. Mark both on the site plan. § 4.106.3 requires the plan to indicate how flows are managed.
- Show roof discharge routing: downspouts tied to underground collection pipes that daylight to the retention garden. On the plan label inlet and outlet locations and the pipe routing. § 4.106.3.
- Hydraulic check (illustrative, not prescribed by CALGreen): assume a 1‑inch storm for a preliminary capacity check — runoff volume = roof area × rainfall depth = 2,000 ft² × (1/12 ft) = ≈167 ft³ (≈1,252 gallons). Design the retention garden to hold or infiltrate the expected runoff (or provide an overflow route). Note: CALGreen § 4.106.3 does not mandate rainfall depth or sizing method; this calculation is an example of demonstrating the measure in the plans.
- Show overflow and emergency route: if retention garden is full, indicate swale bypass or connection to public storm drain so water does not flow toward the foundation. § 4.106.3 requires showing how surface water flows are controlled.
Summary for plan submittal: site plan with labeled swale, retention garden details (surface area, planting media), pipe layout from downspouts, and an overflow route — all clearly tied to the statement that these measures keep water away from the building (meeting § 4.106.3).
Related provisions
- § 4.106.1 — General site development requirements: preservation, slope management, and erosion controls; ties into grading/drainage planning.
- § 4.106.2 — Storm water drainage and retention during construction: retention basins, filter barriers/wattles, and compliance with stormwater ordinances for sites disturbing soil.
- § 4.106.4 — Electric vehicle charging (same § group on site development) — not directly about drainage but adjacent in CALGreen organizationally.
(If you need building‑code slope/distance specifics that affect grading adjacent to foundations, those are in the California Building Code — for example 1804.4 — which references the CALGreen plan requirement; that is a separate code and should be consulted alongside § 4.106.3 for numeric slope requirements.)
Code references
Grounded in the retrieved California Green Building Standards Code (CALGreen) — click a citation to read the verbatim passage:
CALGreen § 4.106.3 High relevance — show source text
(Website: https://www.waterboards.ca.gov/water_issues/programs/stormwater/construction.html)
4.106.3 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings. Examples of methods to manage surface water include, but are not limited to, the following:
Swales
Water collection and disposal systems
French drains
Water retention gardens
Other water measures which keep surface water away from buildings and aid in groundwater recharge.
Exception: Additions and alterations not altering the drainage path.
4.106.4 Electric vehicle (EV) charging for new construction. New construction shall comply with Section 4.106.4.1 or 4.106.4.2. Electric vehicle supply equipment (EVSE) shall comply with the California Electrical Code.
Exceptions:
- On a case-by-case basis, where the local enforcing agency has determined EV charging and infrastructure are not feasible based upon one or more of the following conditions: 1.1. Where there is no local utility power supply or the local utility is unable to supply adequate power.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 4-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
RESIDENTIAL MANDATORY MEASURES
1.2. Where there is evidence suitable to the local enforcing agency substantiating that additional local utility infrastructure design requirements, directly related to the implementation of Section 4.106.4, may adversely impact the construction cost of the project. 2. Accessory Dwelling Units (ADU) and Junior Accessory Dwelling Units (JADU) without additional parking facilities.
4.106.4.1 New one- and two-family dwellings and townhouses with attached private garages. For each dwelling unit, install a listed raceway to accommodate a dedicated 208/240-volt branch circuit. The raceway shall not be less than trade size 1 (nominal 1-inch inside diameter). The raceway shall originate at the main service or subpanel and shall terminate into a listed cabinet, box or other enclosure in close proximity to the proposed location of an EV charger. Raceways are required to be continuous at enclosed, inaccessible or concealed areas and spaces. The service panel and/or subpanel shall provide capacity to install a 40-ampere 208/240-volt minimum dedicated branch circuit and space(s) reserved to permit installation of a branch circuit overcurrent protective device.
Exception: A raceway is not required if a minimum 40-ampere 208/240-volt dedicated EV branch circuit is installed in close proximity to the proposed location of an EV charger at the time of original construction in accordance with the California Elec- trical Code .
4.106.4.1.1 Identification. The service panel or subpanel circuit directory shall identify the overcurrent protective device space(s) reserved for future EV charging as “EV CAPABLE”. The raceway termination location shall be permanently and visibly marked as “EV CAPABLE”.
CALGreen § 4-1 High relevance — show source text
The state agency does not adopt sections identified by the following symbol: †.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 4-1
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
4-2 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
4 RESIDENTIAL MANDATORY MEASURES
DIVISION 4.1 – PLANNING AND DESIGN
SECTION 4.101—GENERAL
4.101.1 Scope. The provisions of this division outline planning, design and development methods that include environmentally responsible site selection, building design, building siting and development to protect, restore and enhance the environmental quality of the site and respect the integrity of adjacent properties.
SECTION 4.102—DEFINITIONS
4.102.1 Definitions. The following terms are defined in Chapter 2.
FRENCH DRAIN.
WATTLES.
SECTION 4.103—SITE SELECTION (RESERVED)
SECTION 4.104—SITE PRESERVATION (RESERVED)
SECTION 4.105—DECONSTRUCTION AND REUSE OF EXISTING STRUCTURES (RESERVED)
SECTION 4.106—SITE DEVELOPMENT
4.106.1 General. Preservation and use of available natural resources shall be accomplished through evaluation and careful planning to minimize negative effects on the site and adjacent areas. Preservation of slopes, management of storm water drainage and erosion controls shall comply with this section.
4.106.2 Storm water drainage and retention during construction. Projects which disturb less than one acre of soil and are not part of a larger common plan of development which in total disturbs one acre or more, shall manage storm water drainage during construction. In order to manage storm water drainage during construction, one or more of the following measures shall be implemented to prevent flooding of adjacent property, prevent erosion and retain soil runoff on the site.
Retention basins of sufficient size shall be utilized to retain storm water on the site.
Where storm water is conveyed to a public drainage system, collection point, gutter or similar disposal method, water shall be filtered by use of a barrier system, wattle or other method approved by the enforcing agency.
Compliance with a lawfully enacted storm water management ordinance.
Note: Refer to the State Water Resources Control Board for projects which disturb one acre or more of soil, or are part of a larger common plan of development which in total disturbs one acre or more of soil.
(Website: https://www.waterboards.ca.gov/water_issues/programs/stormwater/construction.html)
4.106.3 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings. Examples of methods to manage surface water include, but are not limited to, the following:
Swales
Water collection and disposal systems
French drains
Water retention gardens
Other water measures which keep surface water away from buildings and aid in groundwater recharge.
Exception: Additions and alterations not altering the drainage path.
CALGreen § 4.106.2 High relevance — show source text
4.106.2 Storm water drainage and retention during construction. Projects which disturb less than one acre of soil and are not part of a larger common plan of development which in total disturbs one acre or more, shall manage storm water drainage during construction. In order to manage storm water drainage during construction, one or more of the following measures shall be implemented to prevent flooding of adjacent property, prevent erosion and retain soil runoff on the site.
Retention basins of sufficient size shall be utilized to retain storm water on the site.
Where storm water is conveyed to a public drainage system, collection point, gutter or similar disposal method, water shall be filtered by use of a barrier system, wattle or other method approved by the enforcing agency.
Compliance with a lawfully enacted storm water management ordinance.
Note: Refer to the State Water Resources Control Board for projects which disturb one acre or more of soil, or are part of a larger common plan of development which in total disturbs one acre or more of soil.
(Website: https://www.waterboards.ca.gov/water_issues/programs/stormwater/construction.html)
4.106.3 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings. Examples of methods to manage surface water include, but are not limited to, the following:
Swales
Water collection and disposal systems
French drains
Water retention gardens
Other water measures which keep surface water away from buildings and aid in groundwater recharge.
Exception: Additions and alterations not altering the drainage path.
4.106.4 Electric vehicle (EV) charging for new construction. New construction shall comply with Section 4.106.4.1 or 4.106.4.2. Electric vehicle supply equipment (EVSE) shall comply with the California Electrical Code.
Exceptions:
- On a case-by-case basis, where the local enforcing agency has determined EV charging and infrastructure are not feasible based upon one or more of the following conditions: 1.1. Where there is no local utility power supply or the local utility is unable to supply adequate power.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 4-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
RESIDENTIAL MANDATORY MEASURES
1.2. Where there is evidence suitable to the local enforcing agency substantiating that additional local utility infrastructure design requirements, directly related to the implementation of Section 4.106.4, may adversely impact the construction cost of the project. 2. Accessory Dwelling Units (ADU) and Junior Accessory Dwelling Units (JADU) without additional parking facilities.
CALGreen § 103.2 High relevance — show source text
An infill site is selected.
2. A greyfield site is selected.
3. An EPA-recognized Brownfield site is selected.||
|
|
|
|
| |A4.103.2 Facilitate community connectivity by one of the following
methods:
1. Locate project within a1/4-mile true walking distance of at least 4
basic services;
2. Locate project within1/2-mile true walking distance of at least 7
basic services;
3. Other methods increasing access to additional resources.||
|
|
|
|
| |Site Preservation||||||| |A4.104.1An individual with oversight responsibility for the project
has participated in an educational program promoting
environmentally friendly design or development and has provided
training or instruction to appropriate entities.||||||| |Deconstruction and Reuse of Existing Materials||||||| |A4.105.2 Existing buildings are disassembled for reuse or recycling of
building materials. The proposed structure utilizes at least one of the
following materials which can be easily reused:
1. Light fixtures
2. Plumbing fixtures
3. Doors and trim
4. Masonry
5. Electrical devices
6. Appliances
7. Foundations or portions of foundations||||||| |Site Development||||||| |4.106.2A plan is developed and implemented to manage storm water
drainage during construction.||||||| |4.106.3Construction plans shall indicate how site grading or a
drainage system will manage all surface water flows to keep water
from entering buildings.||||||| |4.106.4.1Provide capability for electric vehicle charging for one- and
two-family dwellings; townhouses with attached private garages in
accordance with Section 4.106.4.1.||||||| |4.106.4.2 Provide capability for electric vehicle charging for
multifamily dwellings and hotels/motels in accordance with Sections
4.106.4.2.2 and 4.106.4.2.6.||||||| |4.106.4.3 Provide capability for electric vehicle charging for existing
parking lots or new parking lots for existing residential buildings,CALGreen § 5.106.9 High relevance — show source text
General lighting luminaires in areas such as outdoor parking, sales or storage lots shall meet these reduced ratings. Decorative luminaires located in these areas shall meet_U_-
value limits for “all other outdoor lighting.”|1. IESNA Lighting Zones 0 are not applicable; refer to Lighting Zones as defined in the_California Energy Code_ and Chapter 10 of the_California Administrative Code.
2. For property lines that abut public walkways, bikeways, plazas and parking lots, the property line may be considered to be 5 feet beyond the actual property line for purpose
of determining compliance with this section. For property lines that abut public roadways and public transit corridors, the property line may be considered to be the center-
line of the public roadway or public transit corridor for the purpose of determining compliance with this section.
3. General lighting luminaires in areas such as outdoor parking, sales or storage lots shall meet these reduced ratings. Decorative luminaires located in these areas shall meet_U-
value limits for “all other outdoor lighting.”|5.106.9 Reserved.
5.106.10 Grading and paving. Construction plans shall indicate how site grading or a drainage system will manage all surface water flows to keep water from entering buildings. Examples of methods to manage surface water include, but are not limited to, the following:
Swales.
Water collection and disposal systems.
French drains.
Water retention gardens.
Other water measures which keep surface water away from buildings and aid in groundwater recharge.
Exception: Additions and alterations not altering the drainage path.
5.106.11 Reserved.
5.106.12 Shade trees. [DSA-SS] Shade trees shall be planted to comply with Sections 5.106.12.1, 5.106.12.2 and 5.106.12.3. Percentages shown shall be measured at noon on the summer solstice. Landscape irrigation necessary to establish and maintain tree health shall comply with Section 5.304.6.
5.106.12.1 Surface parking areas. Shade tree plantings, minimum No. 10 container size or equal, shall be installed to provide shade over 50 percent of the parking area within 15 years.
Exceptions: Surface parking area covered by solar photovoltaic shade structures or shade structures with roofing materials that comply with Table A5.106.11.2.2 in Appendix A5 shall be permitted in whole or in part in lieu of shade tree plantings.
5.106.12.2 Landscape areas. Shade tree plantings, minimum No. 10 container size or equal shall be installed to provide shade of 20% of the landscape area within 15 years.
Exception: Playfields for organized sport activity are not included in the total area calculation.
5.106.12.3 Hardscape areas. Shade tree plantings, minimum No. 10 container size or equal shall be installed to provide shade over 20 percent of the hardscape area within 15 years.
Exceptions:
- Walks, hardscape areas covered by solar photovoltaic shade structures or shade structures with roofing materials that comply with Table A5.106.11.2.2 in Appendix A5 shall be permitted in whole or in part in lieu of shade tree plantings.
- Designated and marked play areas of organized sport activity are not included in the total area calculation.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 5-11
CALGreen § 1010.1.4 High relevance — show source text
Exceptions:
- Where climatic or soil conditions warrant, the slope of the ground away from the building foundation shall be permitted to be reduced to not less than 1 unit vertical in 48 units horizontal (2-percent slope).
- Impervious surfaces shall be permitted to be sloped less than 2 percent where the surface is a door landing or ramp that is required to comply with Section 1010.1.4, 1012.3 or 1012.6.1.
The procedure used to establish the final ground level adjacent to the foundation shall account for additional settlement of the backfill.
1804.4.1 [HCD 1] Construction plans. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings in accordance with the California Green Building Standards Code (CALGreen), Chapter 4, Division 4.1.
1804.5 Grading and fill in flood hazard areas. In flood hazard areas established in Section 1612.3, grading, fill, or both, shall not be approved:
- Unless such fill is placed, compacted and sloped to minimize shifting, slumping and erosion during the rise and fall of flood water and, as applicable, wave action.
- In floodways, unless it has been demonstrated through hydrologic and hydraulic analyses performed by a registered design professional in accordance with standard engineering practice that the proposed grading or fill, or both, will not result in any increase in flood levels during the occurrence of the design flood.
- In coastal high hazard areas, unless such fill is conducted or placed to avoid diversion of water and waves toward any building or structure.
- Where design flood elevations are specified but floodways have not been designated, unless it has been demonstrated that the cumulative effect of the proposed flood hazard area encroachment, when combined with all other existing and anticipated flood hazard area encroachment, will not increase the design flood elevation more than 1 foot (305 mm) at any point.
1804.6 Compacted fill material. Where shallow foundations will bear on compacted fill material, the compacted fill shall comply with the provisions of an approved geotechnical report, as set forth in Section 1803.
Exception: Compacted fill material 12 inches (305 mm) in depth or less need not comply with an approved report, provided that the in-place dry density is not less than 90 percent of the maximum dry density at optimum moisture content determined in accordance with ASTM D1557. The compaction shall be verified by special inspection in accordance with Section 1705.6.
1804.7 Controlled low-strength material (CLSM). Where shallow foundations will bear on controlled low-strength material (CLSM), the CLSM shall comply with the provisions of an approved geotechnical report, as set forth in Section 1803.
SECTION 1805—DAMPPROOFING AND WATERPROOFING
1805.1 General. Walls or portions thereof that retain earth and enclose interior spaces and floors below grade shall be waterproofed and dampproofed in accordance with this section, with the exception of those spaces containing groups other than residential and institutional where such omission is not detrimental to the building or occupancy.
Ventilation for crawl spaces shall comply with Section 1202.4.
CALGreen § 4.106.2 High relevance — show source text
The proposed structure utilizes at least one of the
following materials which can be easily reused:
1. Light fixtures
2. Plumbing fixtures
3. Doors and trim
4. Masonry
5. Electrical devices
6. Appliances
7. Foundations or portions of foundations||||||| |Site Development||||||| |4.106.2A plan is developed and implemented to manage storm water
drainage during construction.||||||| |4.106.3Construction plans shall indicate how site grading or a
drainage system will manage all surface water flows to keep water
from entering buildings.||||||| |4.106.4.1Provide capability for electric vehicle charging for one- and
two-family dwellings; townhouses with attached private garages in
accordance with Section 4.106.4.1.||||||| |4.106.4.2 Provide capability for electric vehicle charging for
multifamily dwellings and hotels/motels in accordance with Sections
4.106.4.2.2 and 4.106.4.2.6.||||||| |4.106.4.3 Provide capability for electric vehicle charging for existing
parking lots or new parking lots for existing residential buildings,
hotels/motels in accordance with Section 4.106.4.3, as applicable.||||||| |4.106.4.4Provide bicycle parking facilities as noted below or meet a
local ordinance, whichever is more stringent. Number of bicycle
parking spaces may be reduced, as approved by the enforcing agency,
due to building site characteristics, including but not limited to,
isolation from other development.
1. Provide short-term bicycle parking, per Section 4.106.4.4.1.
2. Provide long-term bicycle parking for multifamily buildings per
Section 4.106.4.4.2.
3. Provide long-term bicycle parking for hotel and motel buildings,
per Section 4.106.4.4.3.||
|
|
|
|
|2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-23
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES
SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued
CALGreen § 5.106.9 High relevance — show source text
Decorative luminaires located in these areas shall meet_U_-
value limits for “all other outdoor lighting.”|1. IESNA Lighting Zones 0 are not applicable; refer to Lighting Zones as defined in the_California Energy Code_ and Chapter 10 of the_California Administrative Code.
2. For property lines that abut public walkways, bikeways, plazas and parking lots, the property line may be considered to be 5 feet beyond the actual property line for purpose
of determining compliance with this section. For property lines that abut public roadways and public transit corridors, the property line may be considered to be the center-
line of the public roadway or public transit corridor for the purpose of determining compliance with this section.
3. General lighting luminaires in areas such as outdoor parking, sales or storage lots shall meet these reduced ratings. Decorative luminaires located in these areas shall meet_U-
value limits for “all other outdoor lighting.”|1. IESNA Lighting Zones 0 are not applicable; refer to Lighting Zones as defined in the_California Energy Code_ and Chapter 10 of the_California Administrative Code.
2. For property lines that abut public walkways, bikeways, plazas and parking lots, the property line may be considered to be 5 feet beyond the actual property line for purpose
of determining compliance with this section. For property lines that abut public roadways and public transit corridors, the property line may be considered to be the center-
line of the public roadway or public transit corridor for the purpose of determining compliance with this section.
3. General lighting luminaires in areas such as outdoor parking, sales or storage lots shall meet these reduced ratings. Decorative luminaires located in these areas shall meet_U-
value limits for “all other outdoor lighting.”|1. IESNA Lighting Zones 0 are not applicable; refer to Lighting Zones as defined in the_California Energy Code_ and Chapter 10 of the_California Administrative Code.
2. For property lines that abut public walkways, bikeways, plazas and parking lots, the property line may be considered to be 5 feet beyond the actual property line for purpose
of determining compliance with this section. For property lines that abut public roadways and public transit corridors, the property line may be considered to be the center-
line of the public roadway or public transit corridor for the purpose of determining compliance with this section.
3. General lighting luminaires in areas such as outdoor parking, sales or storage lots shall meet these reduced ratings. Decorative luminaires located in these areas shall meet_U-
value limits for “all other outdoor lighting.”|5.106.9 Reserved.
5.106.10 Grading and paving. Construction plans shall indicate how site grading or a drainage system will manage all surface water flows to keep water from entering buildings. Examples of methods to manage surface water include, but are not limited to, the following:
Swales.
Water collection and disposal systems.
French drains.
Water retention gardens.
Other water measures which keep surface water away from buildings and aid in groundwater recharge.
Exception: Additions and alterations not altering the drainage path.
5.106.11 Reserved.
CALGreen § 18-6 High relevance — show source text
18-6 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
SOILS AND FOUNDATIONS
SECTION 1804—EXCAVATION, GRADING AND FILL
1804.1 Excavation near foundations. Excavation for any purpose shall not reduce vertical or lateral support for any foundation or adjacent foundation without first underpinning or protecting the foundation against detrimental lateral or vertical movement, or both, in accordance with Section 1803.5.7.
1804.2 Underpinning. Where underpinning is chosen to provide the protection or support of adjacent structures, the underpinning system shall be designed and installed in accordance with provisions of this chapter and Chapter 33.
1804.2.1 Underpinning sequencing. Underpinning shall be installed in a sequential manner that protects the neighboring structure and the working construction site. The sequence of installation shall be identified in the approved construction documents.
1804.3 Placement of backfill. The excavation outside the foundation shall be backfilled with soil that is free of organic material, construction debris, cobbles and boulders or with a controlled low-strength material ( CLSM ). The backfill shall be placed in lifts and compacted in a manner that does not damage the foundation or the waterproofing or dampproofing material.
Exception: CLSM need not be compacted.
1804.4 Site grading. The ground immediately adjacent to the foundation shall be sloped away from the building at a slope of not less than 1 unit vertical in 20 units horizontal (5-percent slope) for a minimum distance of 10 feet (3048 mm) measured perpendicular to the face of the wall. If physical obstructions or lot lines prohibit 10 feet (3048 mm) of horizontal distance, a 5-percent slope shall be provided to an approved alternative method of diverting water away from the foundation. Swales used for this purpose shall be sloped not less than 2 percent where located within 10 feet (3048 mm) of the building foundation. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped not less than 2 percent away from the building.
Exceptions:
- Where climatic or soil conditions warrant, the slope of the ground away from the building foundation shall be permitted to be reduced to not less than 1 unit vertical in 48 units horizontal (2-percent slope).
- Impervious surfaces shall be permitted to be sloped less than 2 percent where the surface is a door landing or ramp that is required to comply with Section 1010.1.4, 1012.3 or 1012.6.1.
The procedure used to establish the final ground level adjacent to the foundation shall account for additional settlement of the backfill.
1804.4.1 [HCD 1] Construction plans. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings in accordance with the California Green Building Standards Code (CALGreen), Chapter 4, Division 4.1.
1804.5 Grading and fill in flood hazard areas. In flood hazard areas established in Section 1612.3, grading, fill, or both, shall not be approved:
- Unless such fill is placed, compacted and sloped to minimize shifting, slumping and erosion during the rise and fall of flood water and, as applicable, wave action.
CALGreen § 2.1 High relevance — show source text
2||||X|||||||||||||||||||| |R325.2.1||||X|||||||||||||||||||| |R325.3||||X|||||||||||||||||||| |R325.4.1||||X|||||||||||||||||||| |R325.8||||X|||||||||||||||||||| |R325.9||||X|||||||||||||||||||| |R326||||X|||||||||||||||||||| |R327.1||||X|||||||||||||||||||| |Figure R327.1||||†|||||||||||||||||||| |R328||||X|||||||||||||||||||| |R329|||X||||||||||||||||||||| |R329.2||||X|||||||||||||||||||| |R330|||X||||||||||||||||||||| |R331|||X||||||||||||||||||||| |R332|||X||||||||||||||||||||| |R334||||X|||||||||||||||||||| |R334.1||||X|||||||||||||||||||| |R335|||X||||||||||||||||||||| |R336|||X||||||||||||||||||||| |R337 User Note|||X|X|||||||||||||||||||| |R338 - R338.4|||X||||||||||||||||||||| |R340||||X|||||||||||||||||||| |R340.1||||X||||||||||||||||||||
The state agency does not adopt sections identified with the following symbol: † The � designation indicates that the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures subject to HCD 1.
2025 CALIFORNIA RESIDENTIAL CODE 3-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
3-4 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
Part III— Building Planning and Construction
3 BUILDING PLANNING
User notes:
About this chapter: Chapter 3 contains a wide array of building planning requirements that are critical to designing a safe and usable building. This includes, but is not limited to, requirements related to general structural design, fire-resistant construction, light, ventilation, sanitation, plumbing fixture clearances, minimum room area and ceiling height, safety glazing, means of egress, automatic fire sprinkler systems, smoke and carbon monoxide alarm systems, accessibility and solar energy systems.
SECTION R300—SITE DRAINAGE
R300.1 Storm water drainage and retention during construction. Projects which disturb less than one acre of soil and are not part of a larger common plan of development which in total disturbs one acre or more, shall manage storm water drainage during construction in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.
R300.2 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.
SECTION R301—DESIGN CRITERIA
CALGreen § 3-3 High relevance — show source text
2025 CALIFORNIA RESIDENTIAL CODE 3-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
3-4 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
Part III— Building Planning and Construction
3 BUILDING PLANNING
User notes:
About this chapter: Chapter 3 contains a wide array of building planning requirements that are critical to designing a safe and usable building. This includes, but is not limited to, requirements related to general structural design, fire-resistant construction, light, ventilation, sanitation, plumbing fixture clearances, minimum room area and ceiling height, safety glazing, means of egress, automatic fire sprinkler systems, smoke and carbon monoxide alarm systems, accessibility and solar energy systems.
SECTION R300—SITE DRAINAGE
R300.1 Storm water drainage and retention during construction. Projects which disturb less than one acre of soil and are not part of a larger common plan of development which in total disturbs one acre or more, shall manage storm water drainage during construction in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.
R300.2 Grading and paving. Construction plans shall indicate how the site grading or drainage system will manage all surface water flows to keep water from entering buildings in accordance with the California Green Building Standards Code, Chapter 4, Division 4.1.
SECTION R301—DESIGN CRITERIA
R301.1 Application. Buildings and structures, and parts thereof, shall be constructed to safely support all loads, including dead loads, live loads, roof loads, flood loads, snow loads, wind loads and seismic loads as prescribed by this code. The construction of buildings and structures in accordance with the provisions of this code shall result in a system that provides a complete load path that meets the requirements for the transfer of loads from their point of origin through the load-resisting elements to the foundation. Buildings and structures constructed as prescribed by this code are deemed to comply with the requirements of this section.
Existing buildings housing existing protective social care homes or facilities established prior to 1972 (see Chapter 11 of the California Fire Code and the California Existing Building Code).
R301.1.1 Alternative provisions. As an alternative to the requirements in Section R301.1, the following standards are permitted subject to the limitations of this code and the limitations therein. Where engineered design is used in conjunction with these standards, the design shall comply with the California Building Code .
- AWC Wood Frame Construction Manual (WFCM).
- AISI Standard for Cold-Formed Steel Framing—Prescriptive Method for One- and Two-Family Dwellings (AISI S230).
- ICC Standard on the Design and Construction of Log Structures (ICC 400).
R301.1.1.1 Alternative provisions for limited-density owner-built rural dwellings. The purpose of this subsection is to permit alternatives that provide minimum protection of life, limb, health, property, safety and welfare of the general public and the owners and occupants of limited-density owner-built rural dwellings as defined in Chapter 2 of this code. For additional informa- tion see Chapter 1, Subchapter 1, Article 8, of Title 25, California Code of Regulations, commencing with Section 74.
CALGreen § 105.3 High relevance — show source text
BENCH. A relatively level step excavated into earth material on which fill is to be placed.
COMPACTION. The densification of a fill by mechanical means.
CUT. See “Excavation.”
DOWN DRAIN. A device for collecting water from a swale or ditch located on or above a slope, and safely delivering it to an approved drainage facility.
EROSION. The wearing away of the ground surface as a result of the movement of wind, water or ice.
EXCAVATION. The removal of earth material by artificial means, also referred to as a cut.
FILL. Deposition of earth materials by artificial means.
GRADE. The vertical location of the ground surface.
GRADE, EXISTING. The grade prior to grading.
GRADE, FINISHED. The grade of the site at the conclusion of all grading efforts.
GRADING. An excavation or fill or combination thereof.
KEY. A compacted fill placed in a trench excavated in earth material beneath the toe of a slope.
SLOPE. An inclined surface, the inclination of which is expressed as a ratio of horizontal distance to vertical distance.
TERRACE. A relatively level step constructed in the face of a graded slope for drainage and maintenance purposes.
SECTION J103—PERMITS REQUIRED
J103.1 Permits required. Except as exempted in Section J103.2, grading shall not be performed without first having obtained a permit therefor from the building official. A grading permit does not include the construction of retaining walls or other structures.
J103.2 Exemptions. A grading permit shall not be required for the following:
Grading in an isolated, self-contained area, provided that the public is not endangered and that such grading will not adversely affect adjoining properties.
Excavation for construction of a structure permitted under this code.
Cemetery graves.
Refuse disposal sites controlled by other regulations.
Excavations for wells, or trenches for utilities.
APPENDIX J-2 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX J—GRADING
- Mining, quarrying, excavating, processing or stock-piling rock, sand, gravel, aggregate or clay controlled by other regulations, provided that such operations do not affect the lateral support of, or significantly increase stresses in, soil on adjoining properties.
- Exploratory excavations performed under the direction of a registered design professional.
Exemption from the permit requirements of this appendix shall not be deemed to grant authorization for any work to be done in any manner in violation of the provisions of this code or any other laws or ordinances of this jurisdiction.
SECTION J104—PERMIT APPLICATION AND SUBMITTALS
J104.1 Submittal requirements. In addition to the provisions of Section 105.3 and 1.8.4, as applicable, the applicant shall state the estimated quantities of excavation and fill.
J104.2 Site plan requirements. In addition to the provisions of Section 107, a grading plan shall show the existing grade and finished grade in contour intervals of sufficient clarity to indicate the nature and extent of the work and show in detail that it complies with the requirements of this code. The plans shall show the existing grade on adjoining properties in sufficient detail to identify how grade changes will conform to the requirements of this code.
Frequently asked questions
When does § 4.106.3 apply?
It applies to projects that require construction plans: plans must indicate how site grading or drainage will manage surface water flows so water does not enter buildings. Additions/alterations that do not change the drainage path are excepted. § 4.106.3.
Must I size drains or retention basins on the CALGreen plan?
§ 4.106.3 does not prescribe numeric sizing — it requires the plans to indicate how flows are managed. Jurisdictional or local stormwater rules, or engineering practice, will dictate sizing and may be required on the plans. Also see § 4.106.2 for construction‑phase controls.
Are the example measures in § 4.106.3 exhaustive?
No. The section lists examples (swales, collection systems, French drains, retention gardens) but allows “other water measures” that accomplish the same objective if shown on the plans. § 4.106.3.
What if my project disturbs less than one acre?
If the project disturbs less than one acre (and is not part of a larger plan that totals ≥ one acre), you still must manage storm water during construction using measures in § 4.106.2 (retention basins, filter barriers, or a lawful local ordinance).
If I show a retention garden, do I also need a swale?
Not necessarily. You must show that surface water will be kept from entering the building; the combination of measures you choose should provide that assurance. If the retention garden cannot handle overflow, the plan should show the overflow path (which could be a swale). § 4.106.3.
More in California Green Building Standards Code (CALGreen)
- Administration (Chapter 1)
- Nonresidential Voluntary Measures (Appendix A5 — divisions A5.1–A5.6, electives & verification)
- Residential Mandatory Measures — Planning & Design; Energy; Water; Materials; Environmental Quality (Chapter 4)
- Definitions (Chapter 2)
- Voluntary Standards for Health Facilities (Appendix A6 / OSHPD guidance)
- Green Building – scope, mixed occupancies, phased projects (Chapter 3)
- Residential Voluntary Measures (Appendix A4 — divisions A4.1–A4.6, tiers & model ordinance)
- Nonresidential Mandatory Measures — Planning & Design; Energy; Water; Materials; Environmental Quality (Chapter 5)
- Compliance verification, construction documents & checklists (Section 102, Chapter 7, Appendix checklists)
- Referenced Organizations and Standards (Chapter 6)
- Voluntary Tiers and CALGreen Tier 1 / Tier 2 (performance tiers, thresholds)
- Installer and Special Inspector Qualifications (Chapter 7)
Ask about the CALGreen
Get cited, plain-English answers on the California Green Building Standards Code (CALGreen) for your project — any code section, any scenario.
Start Free Trial