Chapter 25B — WATER WELL CONSTRUCTION STANDARDS

Editor's note— Ord. No. 6422, § I(Exh. A), adopted April 18, 2023, amended Ch. 25B in its entirety to read as herein set out. Former Ch. 25B, §§ 25B-1—25B-11, pertained to similar subject matter and derived from Ord. No. 6121, § III(Exh. A), adopted July 28, 2015; and Ord. No. 6331, § II(Exh. C), adopted Dec. 15, 2020.

Article I. - In General.

(a)

A significant component of water used in Sonoma County is obtained from underground sources.

(b)

Improperly placed, constructed, reconstructed, abandoned or destroyed wells, or borings, as defined in this chapter, may allow contaminated water from the surface or subsurface strata to migrate and contaminate useable ground waters.

(c)

The people of Sonoma County have a primary interest in the protection of groundwater resources, as contamination or depletion of groundwater may cause serious public health, safety, environmental or economic problems.

(d)

California courts have found that state agencies must consider the public trust doctrine and exercise their discretion regarding it when evaluating the issuance of permits to extract groundwater that may adversely affect public trust resources of interconnected navigable waters.

(Ord. No. 6422, § I(Exh. A), 4-18-2023)

(a)

The purpose of this chapter is to protect the environment, public health and safety, and the groundwater resource of the county through standards regulating the placement, construction, reconstruction, abandonment and destruction of wells and borings.

(b)

It is further the purpose of this chapter to address the County's public trust obligation and to document the County's exercise of its discretion regarding how it will evaluate the public trust when considering permits to extract groundwater that may adversely affect public trust resources in interconnected navigable waters.

(c)

This chapter shall apply (1) in the unincorporated area of the county, and (2) within each city that has not appointed its own Health Officer.

(Ord. No. 6422, § I(Exh. A), 4-18-2023)

The following words, terms and phrases, when used in this chapter, shall have the meanings ascribed to them in this section, except where the context clearly indicates a different meaning:

"Abandoned boring" means a boring that has not been properly refilled with cuttings and/or grout, as applicable, after construction has been completed, unless otherwise approved by the enforcing agency.

"Abandoned well" means a well, other than an "inactive well," whose use has been discontinued for one (1) year or longer, or has been permanently discontinued, or is in such a state of disrepair that it cannot be used for its original purpose.

"Annular seal" means a watertight seal of approved material placed between the well casing and the sidewall of the boring excavation.

"Annular space" means the space between an excavation and the casing of a well or the space between two (2) concentric casings.

"Bacteriological compounds" mean bacteria, viruses, and protozoa that are disease causing agents (pathogenic) commonly found in the human or animal gut.

"Boring" means an artificially constructed, generally uncased, temporary hole below the original ground surface, made with rotary, air, water jet, direct push or similar technology, for the purpose of exploration of the subsurface of the earth for building or structure foundation, presence of water, or any other purpose other than construction of a well.

"Cathodic protection well" means a well constructed for the purpose of installing equipment or facilities for the electrical protection of metallic equipment in contact with the ground.

"Class I well" means a well constructed with a minimum twenty-foot deep annular seal. "Class II well" means a well constructed with a minimum fifty-foot deep annular seal.

"Contaminant" means any physical, chemical, biological, or radiological substance or matter in water or soil that has potential to result in an adverse effect on human or animal health.

"Contaminated site" means a site that has soil or groundwater contamination that exceeds California Primary Maximum Contaminant Levels (MCLs).

"Contaminated well" means a well that produces groundwater that exceeds California Primary MCLs. "Contamination" means any contaminant that exceeds the California Primary MCLs.

"Destroyed well or boring" means a well or boring that has been destroyed pursuant to this chapter.

"Dewatering well" means an artificial excavation constructed by any method for the removal or hydraulic control of groundwater for construction purposes or during a groundwater or soil remediation project.

"Drilling fluid" means a fluid used in drilling operations to remove cuttings from the borehole, to clean and cool the bit, to reduce friction between the drill stem and the borehole wall, and to prevent caving or sloughing of the borehole. "Elevator jack shaft" means a device designed to house hydraulic ram equipment used to lift an elevator. An elevator jack shaft is housed in a borehole drilled and a casing advanced.

"Embankment reservoir" means an off-stream reservoir that utilizes embankments or manmade structures to impound water.

"Environmental drilling" means the subsurface exploration for contaminants and hazardous substances that may potentially impact soil and groundwater.

"Environmental well" means any artificial excavation by any method for the purpose of monitoring fluctuations in groundwater levels, quality of underground waters, or the concentration of contaminants in underground waters related to environmental remediation sites, or for the purpose of extraction or hydraulic control over contaminants or contaminated groundwater, or for the purpose of in-situ treatment of contaminated groundwater.

"Enforcing agency" means the agency identified by Table 25B-1 as having the responsibility and authority to review, and approve or deny the permit applications described in this chapter.

"Feed yard/lot" means commercial corrals or commercial holding areas for the primary purpose of holding or feeding animals (including fowl).

"Geothermal heat exchange well" means any uncased artificial excavation, by any method, that uses the heat exchange capacity of the earth for heating and cooling, in which excavation the ambient ground temperature is thirty (30) degrees Celsius (eighty-six (86) degrees Fahrenheit) or less, and which excavation uses a closed loop fluid system to prevent the discharge or escape of its fluid into surrounding aquifers or other geologic formations. Geothermal heat exchange wells include ground source heat pump wells.

"Geotechnical boring" means any boring constructed in the earth below the original ground surface solely for exploring or testing subsurface earth or groundwater.

"Groundwater availability area" means the four (4) zones depicted on the map entitled "groundwater availability" which is on file with the Sonoma County permit and resource management department and available for public inspection.

"Grout" means a fluid mixture of cement and water of a consistency that can be forced through a pipe and placed as required. Various additives, such as sand, bentonite, and hydrated lime, are used to meet certain requirements. For example, sand is added when considerable volume of grout is needed.

"Hazardous material" means a material or substance that poses substantial or potential threats to public health or the environment.

"High volume well" means a well intending to serve twenty (20) or more acres of irrigated crops; a municipal well intending to serve fifteen (15) or more connections; or a commercial/industrial well intending to deliver thirty-five thousand (35,000) or more gallons per day.

"Horizontal well" means a water wells drilled horizontally or at an angle with the horizon (as contrasted with the common vertical well). This definition does not apply to horizontal drains or "wells" constructed to remove subsurface water from hillsides, cuts, or fills (such installations are used to prevent or correct conditions that produce landslides).

"Inactive well" means a well whose use has been discontinued and the owner has declared in writing to the enforcing agency the intention to use such well again for supplying water or for other approved purposes.

"Individual water well" means a water well furnishing water for human consumption and general use to four (4) or less service connections or serves an average of less than twenty-five (25) individuals daily.

"Inorganic compounds" mean any compound that does not contain carbon. For purposes of this ordinance, inorganic compounds refer to the MCLs for inorganics and include materials such as fertilizers or decayed organic materials, chlorides, and mineral metals.

"Known contaminated sites" are those identified on the state water resources control board databases (landfills, underground storage tanks, etc.) or areas known to governmental bodies that have groundwater and/or soil contamination.

"Lake" means a permanent natural body of water of any size, or an artificially impounded body of water having a source area of at least one (1) acre, isolated from the sea, and having an area of open water of sufficient depth and permanency to prevent complete coverage by rooted aquatic plants. As used in this chapter, lake does not include embankment reservoirs.

"Maximum contaminant level (MCL)" means the highest level of a contaminant that is allowed in drinking water by the state of California.

"Monitoring well" means any artificial excavation by any method for the purpose of monitoring fluctuations in groundwater levels or the quality of underground waters or studying the hydrologic conditions, except as exempt pursuant to Water Code Section 13712.5 as to crop root zones.

"Navigable waters" means waterways capable of being navigated by oar or motor-propelled small craft, consistent with the California public right of navigation test.

"Piezometer" means any of various instruments used to determine water elevations in wells by measuring the static liquid pressure.

"Pond" means a still, freshwater body that is smaller than a lake and often manmade. A pond can provide water for livestock, fish and wildlife, recreations, fire control, crop and orchard watering, and other related uses. As used in this chapter, pond does not include embankment reservoirs.

"Potable ground water" means water below the surface of the ground at a depth such that it has been protected from surface contamination by an impervious soil stratum or which has received an acceptable degree of natural treatment by filtration through a considerable amount of soil.

"Potable water" means water intended for human consumption which meets, at a minimum, state primary drinking water requirements as defined in Title 22 of the California Code of Regulations (or subsequent revisions) whether this water is supplied from ground water, treated ground water or any other source.

"Public water well" means a water well furnishing water for human consumption and general use to five (5) or more service connections or serves an average of at least twenty-five (25) individuals daily at least sixty (60) days out of the year.

"Public trust resources" means waterways and associated uses the government is obligated to hold in trust pursuant to the public trust doctrine for the benefit of the public for purposes of commerce, navigation, recreation, fishing, and preservation of wildlife habitat and natural resources.

"Public Trust Review Area" means the mapped land area specified in section 25B-4(d)(2), which is shown by Figure 25B-14a.

"Replacement well" means the construction of a new well to replace an existing well where the existing well is destroyed under permit within ninety (90) days of completion of the replacement well.

"Sewage disposal system" means a septic tank and subsurface disposal field or other type system or appurtenance thereto, whether public or private, receiving domestic or industrial sewage waste. Sewage disposal system includes proposed onsite sewage disposal areas for which appropriate testing has been approved. Sewage disposal system does not include a sewer pipe line.

"Special flood hazard area" means any area designated by the Federal Emergency Management Agency as subject to flooding by the one-percent annual chance flood (100-year flood).

"Stream" means any natural channel with bed and banks containing flowing water or showing evidence of having contained flowing water (e.g. deposit of sand, gravel, or soil).

"Site" means any lot or parcel of land or contiguous combination thereof where well construction or reconstruction is performed or permitted.

"Test well" means a well constructed to obtain information needed for design of other wells. Test wells should not be confused with "exploration holes", which are temporary. Test wells are cased and can be converted to other uses such as groundwater monitoring and, under certain circumstances, to production wells.

"Water quality" means the chemical, physical, radiological, biological, taste and/or odor characteristics of water with respect to its suitability for a particular purpose.

"Well or water well" means any artificial excavation constructed by any method for the purposes of extracting water from, or injecting water into, the underground. This definition shall not include: (a) oil and gas wells, or geothermal wells constructed under the jurisdiction of the department of conservation, except those wells converted to use as water wells; or (b) wells used for the purpose of (1) dewatering excavations during construction, or (2) stabilizing hillsides or earth embankments; or (c) infiltration galleries and springs.

"Well development" means the act of cleaning out the clay and silt introduced during the drilling process as well as the finer particles of the aquifer directly around the well screen prior to putting the well into service.

"Well drilling contractor" means a person who is a licensed water well driller in the state of California and holds a valid C-57 contractor's license and who maintains a current workers' compensation insurance certificate on file with the enforcing agency.

"Well reconstruction" means and includes certain work done to an existing water well in order to restore its production, replace defective casing, seal off certain strata or surface water or similar work. Well reconstruction does not include internal relining, the cleaning out of sediments or surging, or maintenance to the pump or appurtenances where the integrity of the annular seal or water bearing strata are not violated.

"Well seal" means a water resistant joint between the pump or its plumbing and the well casing, or between the pump base and the concrete platform.

"Well site" means the area surrounding the well having a circular shape with a radius of ten feet (10') centered at the well head.

"Well vault" means a feature below the ground surface used to house the top of a well casing, a pump and/or a discharge pipe.

"Wetland" means those areas that meet either the federal definition of wetlands, as set forth in 33 CFR § 328.3, as that section may be amended from time to time, or the state of California definition of wetland as adopted by the State Water Resources Control Board as a State Wetland Definition, as that definition may be

amended from time to time. In the event of a conflict between the federal and state definitions, whichever definition is more protective shall control.

(Ord. No. 6422, § I(Exh. A), 4-18-2023)

(a)

Wells.

(1)

The construction or installation of a new well within a stream or wetland is prohibited.

(b)

In areas where there is an adopted groundwater management plan or applicable ground water sustainability plan, the requirements of any permit issued under this Chapter exist independent of and in addition to any plan requirements, such that the more protective of the permit or plan requirements will ultimately govern.

(c)

No well shall be used for the disposal of any substance or liquid that may contaminate the groundwater.

(d)

Public trust review. This section addresses how the county of Sonoma fulfills its obligation to consider and protect against adverse impacts of new water wells on public trust resources and uses.

(1)

All water well applications shall be reviewed for potential adverse impacts on public trust resources, except as provided in this Chapter.

(2)

Public Trust Review Area. The Public Trust Review Area is the area represented by Figure 25B-14a, which the Board of Supervisors determined is the area estimated to be where the underlying aquifer is interconnected with navigable surface waters or a tributary stream that flows to a navigable water, and which is based on available information indicating groundwater extraction may impact public trust resources including instream habitat of anadromous fish. See map of the Public Trust Review Area at section 25B-14, Figure 25B-14a. The Enforcing Agency will maintain an interactive version of the Public Trust Review Area map for ease of viewing that is searchable by parcel or address. The Public Trust Review Area map is controlling for purposes of determining whether the location of a proposed well is within the Public Trust Review Area. From time to time, in its discretion, the Board of Supervisors may update the Public Trust Review Area map.

(3)

Application Information. In addition to materials otherwise required by this Chapter, an applicant for a water well permit within the Public Trust Review Area shall provide as part of its application information to the satisfaction of the Enforcing Agency that is sufficient for the Enforcing Agency to determine that the issuance of the water well permit within a Public Trust Review Area will or will not cause or exacerbate a substantial adverse impact on public trust resources after imposition of all feasible mitigation measures that can be imposed to protect the public trust resources.

(4)

Findings and Determination. As part of the issuance, issuance with conditions, or denial of any water well permit within the Public Trust Review Area, the Enforcing Agency shall consider best available information and make written findings as to whether the issuance of the requested permit will or will not cause or exacerbate a substantial adverse impact on public trust resources after the imposition of feasible mitigation measures to protect those public trust resources. Any project features or mitigation measures that are necessary to the Enforcing Agency's written findings for approval of any new water well permit shall become conditions on the new water well permit.

(5)

Information. Best available information, including but not limited to adopted groundwater sustainability plans, hydrologic and hydrogeologic reports, biological opinions, minimum instream flows adopted by a state or federal agency, amongst other information, shall be used to determine a substantial adverse impact to Public Trust Resources for the project. Geographic and temporal proximity of best available information to the proposed well may be considered by the Enforcing Agency.

(6)

Administrative Appeal. Any interested person may appeal the determination made by the Enforcing Agency under subsection (d)(4) to the Board of Supervisors. An appeal shall be filed in writing with the planning director within ten (10) days after the decision that is the subject of the appeal; provided, however, that the county may still revoke any erroneously issued permit or entitlement even after the expiration of the ten-day appeal period. The appeal shall specifically state the basis for the appeal and shall be accompanied by the required filing fee.

(7)

Request for Overriding Considerations. At the request of the Enforcing Agency, the Board of Supervisors, after holding a public hearing, and based on written findings of overriding considerations that balance the protection of public trust resources with the health, safety and welfare needs of the community, including the need for drinking water, may approve the issuance of a water well permit or issuance with conditions.

(8)

The Board of Supervisors may consolidate and concurrently consider an appeal filed pursuant to subsection (d)(6) and a request for written findings of overriding considerations pursuant to subsection (d)(7).

(e)

Notwithstanding any provision of this Chapter, and notwithstanding location within the Public Trust Review Area, the following proposed wells are exempt from discretionary public trust review due to the low potential for impacts to public trust resources or due to the overriding public interest in favor of ensuring adequate water supply for existing and domestic uses:

(1)

A water well for which a well application is determined to be complete by the enforcing agency prior to October 4, 2022.

(2)

A water well outside the Public Trust Review Area.

(3)

A water well that is used solely for injecting water into the underground.

(4)

Public Water Well. A public water well for which environmental review under the California Environmental Quality Act is complete.

(5)

Surface Water Diversion Well. A water well that serves as a point of surface water diversion for an appropriative water right regulated by the California State Water Resources Control Board, Division of Water Rights, and where the owner or user of the well complies with all applicable Level 1 water conservation and monitoring requirements listed in Article VIII.

(6)

Well for Low Water Use. A water well where the cumulative groundwater use from all wells on the parcel, including the proposed well, is limited to two (2) acre feet or less per year, and where the owner or user of the well complies with all applicable Level 1 water conservation and monitoring requirements listed in Article VIII.

(7)

Well for Existing Use. A water well where the cumulative groundwater use from all wells on the parcel, including the proposed well, is limited to the amount of groundwater used for legally established land uses that existed as of October 4, 2022, and where the owner or user of the well complies with all applicable Level 1 and Level 2 water conservation and monitoring requirements listed in Article VIII.

(8)

Net Zero Groundwater Increase. A water well where the proposed use of water may increase but not result in a net increase in groundwater use from the local aquifer through implementation of water conservation measures, rainwater catchment or recycled water reuse system, water recharge project, agricultural practices that increase infiltration and soil moisture capacity, local groundwater management project, or participation in a streamflow augmentation project authorized by the California Department of Fish and Wildlife or National Marine Fisheries Service, provided that:

(i)

The owner or user of the well complies with all applicable Level 1 and Level 2 water conservation and monitoring requirements listed in Article VIII; and

(ii)

The applicant submits a groundwater recharge plan and report that documents enhanced ground water recharge that is equal to the proposed net increase in groundwater extraction. The plan and report shall be prepared by a qualified professional with experience in hydrogeology.

(Ord. No. 6422, § I(Exh. A), 4-18-2023)