Local zoning · Monrovia

Monrovia — Nonconforming Uses

Nonconforming Uses under the Monrovia local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

Monrovia’s Zoning Title (Title 17) treats nonconforming uses and nonconforming structures as temporary, allowable conditions that must not be expanded except where the code explicitly permits it. The core rules sit in Chapter 17.48 (intent, continuation, repairs, abandonment, reconstruction and special rules for wireless facilities) and are applied together with zone-specific rules (for example HCD and the West Huntington corridor). See the controlling rules at § 17.48.010 through § 17.48.070 for the citywide framework.

Note: when the code refers to bringing a building into compliance it often means compliance with building and safety regulations in addition to Title 17 zoning rules—consult the state California Building Standards Code for building-safety standards referenced by the City. (Verify with the jurisdiction for parcel‑specific application.)

How to read this page

  • Bold = terms you’ll scan for (zoning districts, numeric thresholds, key § citations).
  • Inline links: first natural mention of related topics links to the Monrovia menu items (parking, design review, overlays, ADUs, development standards, and the State building code).

Citywide nonconforming rules (what the code actually says)

  • The City’s policy statement is that nonconforming uses/structures are tolerated temporarily but not encouraged (§ 17.48.010). Continued use is allowed only subject to the limitations below.

  • Continuation rules for nonconforming uses: a lawful nonconforming use may continue but may not be enlarged, moved, extended beyond the originally authorized structure or area, and may not resume if superseded by a permitted use. Abandonment for a continuous period of 180 days causes loss of status (see items below). § 17.48.020.

  • Changing to another nonconforming use: allowed only if Development Review Committee (DRC) finds the new use is “equally or more appropriate” to the district and imposes conditions to avoid increased nonconformity (§ 17.48.020(D)). Link: Monrovia Design Review.

  • Nonconforming structures:

    • May be continued but may not be altered in ways that increase nonconformity; alterations that decrease nonconformity are allowed (§ 17.48.030(A)).
    • If a nonconforming structure is destroyed more than 50% of its replacement value, it generally cannot be rebuilt nonconforming (with a residential reconstruction exception noted below) (§ 17.48.030(B)).
    • Abandonment / vacancy of 180 days or more: subsequent uses must conform (§ 17.48.030(F) and § 17.48.020(F)).

  • Repairs and maintenance: allowed, but the value of repair/replacement in any 12‑month period cannot exceed 10% of the replacement cost of the whole structure; the square footage may not be increased by such repairs (§ 17.48.040).

  • Nonconformity caused by density changes: the code allows limited enlargements/reconstructions when a legal use becomes nonconforming only because the allowed density changed — subject to DRC approval and recording of a covenant (§ 17.48.050).

  • Loss of legal status: the right to continue a nonconforming use ends if the use is declared a public nuisance via Chapter 8.12 procedures; the Council may allow a CUP application in some nuisance cases (§ 17.48.060).

  • Wireless facilities: special amortization/conformity schedule — pre‑existing wireless facilities that became nonconforming must generally be brought into conformance within 10 years and are subject to separate abandonment rules (90 days) (§ 17.48.070) and Chapter 17.46 procedures.

  • Special downtown rules: Historic Commercial Downtown (HCD) and other corridor-specific rules may provide narrower or alternative rules for expanding uses that become nonconforming; the HCD chapter contains a specific nonconforming‑use expansion path via CUP in limited cases (§ 17.14.030 and cross‑references to § 17.08.020(D)).

Practical links: when the code says “parking” or requires additional parking to allow an expansion, see the City’s Monrovia Parking rules and the build‑out standards at Monrovia Development Standards.

District-by-district summary (purpose, typical uses, key dimensional standards, where it applies)

Note: this page focuses on how nonconformity is treated in each district—use the cited sections for the full permitted‑use tables and dimensional rules.

RF — Residential Foothill

  • Purpose: RF protects low‑density foothill neighborhoods; large lots and limited development intensity. § 17.12.010.
  • Typical permitted uses: single‑family dwellings, limited accessory structures. See chapter for accessory F.A.R. limits. § 17.12.010(C).
  • Key dimensional standards: minimum lot area 15,000 sq ft, front setback 25 ft, accessory F.A.R. caps (under one acre 10% / max 2,000 sq ft) § 17.12.010.
  • Nonconforming notes: standard citywide nonconforming rules apply (abandonment, repairs cap 10%, destruction > 50%) — see § 17.48.020–.040.

RE / RL — Residential Estate / Residential Low Density

  • Purpose and uses: larger single‑family lots and low density; see chapter lists in Title 17 (district index § 17.04.030).
  • Dimensional highlights: setback and lot‑coverage rules vary by RF/RE/RL; front setbacks commonly 25 ft, side yard formulas set as percent of lot width — check local section for the exact table. See relevant residential sections in Chapter 17.12.
  • Nonconforming notes: same citywide rules; DRC/Committee can consider minor exceptions where allowed (§ 17.52.110) — especially relevant when altering nonconforming lots or structures.

RM / RM‑PUD / RM/RH / RH — Medium / High Density Residential

  • Purpose: RM and RH regulate multifamily development (apartments, condominiums, PUDs). See multiple‑family standards in § 17.12.030 and related tables.
  • Typical uses: multi‑family dwellings (permitted), senior housing (C or P depending), ADUs rules also apply (see city ADU chapter).
  • Key dimensional standards: front yard 25 ft (RM/RH), side setbacks tied to lot width (10% with 5' min / 15' max), second‑story setbacks (RM: 8 ft, RH: 6 ft), FAR caps (RM zones 40%; RM/RH and RH have higher FARs) (see § 17.12.030 / 17.12.0xx).
  • Nonconforming notes: adding an ADU or converting space can trigger a requirement that “all structures on the property shall meet building and safety regulations” and that existing structures be brought into conformity “to the extent reasonable and feasible” (see § 17.48.030(C)). Link: Monrovia ADUs.

NC / CRS / RCC / RCM — Commercial and Retail Corridor Zones

  • Purpose: commercial corridors and downtown cores; RCM (Retail Corridor Mixed Use) and RCC (Retail Corridor Commercial) have specific standards for West Huntington Drive (§ 17.16.050) and include rules allowing limited expansion of nonconforming uses via CUP when consistent with corridor plans.
  • Typical uses: street‑level retail, offices, mixed residential above retail (RCM permits residential up to 54 du/acre) § 17.16.050.
  • Key dimensional standards: RCM FAR with surface parking 2.0 (structured parking allows higher FAR), building setback guidance (front setbacks frequently 10 ft in RCC, reducible by DRC). § 17.16.050.
  • Nonconforming notes: HCD downtown and RCM allow conditional expansion of uses that became nonconforming under specified findings; see § 17.14.030 and § 17.08.020(D) for the special references matrix. Monrovia Overlay Districts is relevant for corridor overlays.

HCD — Historic Commercial Downtown

  • Purpose and special treatment: HCD recognizes historic downtown character and includes an explicit path for expanding existing nonconforming uses in controlled circumstances via CUP (§ 17.14.030) and cross‑references to West Huntington and Land Use Element goals.
  • Nonconforming notes: § 17.14.030 allows expansion on finding consistency with the downtown plan — this is an exception to the general "no expansion" rule and must be handled through the Commission/CUP process.

ANF — Angeles National Forest Zone

  • Purpose & limits: ANF applies to privately owned land inside the Angeles National Forest boundary within the city; extremely limited uses (utility distribution, seasonal vacation cabins) and minimum lot areas (80 acres) § 17.18.010.
  • Nonconforming notes: the usual nonconforming rules apply, but the zone’s extreme limitations make nonconforming rights narrow—verify site‑specific applicability before assuming any expansion is allowed.

Quick Decision table (most decision‑relevant standards / permissions)

What you need to know Rule / limit Code Reference
Continue a nonconforming use (general) Allowed if in compliance with laws other than the use regs; may not be enlarged/moved/extended § 17.48.020
Change nonconforming use to another nonconforming use Allowed only with DRC finding that new use is equally or more appropriate; conditions may be imposed § 17.48.020(D)
Repairs/maintenance limit Repair value in any 12‑month period ≤ 10% of replacement cost; no net square footage increase § 17.48.040
Destruction / reconstruction threshold If > 50% destroyed, cannot be reconstructed nonconforming except limited residential exceptions § 17.48.030(B)
Abandonment / vacancy period 180 days continuous vacancy ≈ loss of status (90 days for wireless facilities) § 17.48.020(F); § 17.48.070(B)(2)
HCD / corridor expansion HCD and some corridors allow expansion by CUP when specific findings met § 17.14.030; § 17.16.050(D)
Wireless facility amortization Owner must bring into conformity within 10 years or seek other remedies; special procedures in Chapter 17.46 § 17.48.070; Chapter 17.46

Checklist — what an applicant must do (nonconforming uses / structures)

  • Confirm the property’s nonconforming status (was the use lawful when established?) — check title records and permits; cite § 17.48.010.
  • Check for abandonment or vacancy periods (180 days general; 90 days for wireless) — § 17.48.020(F) and § 17.48.070(B)(2).
  • If proposing a change of nonconforming use, prepare a DRC application showing the new use is equally or more appropriate and propose mitigation conditions — § 17.48.020(D) and see Monrovia Design Review.
  • If proposing repairs: prepare cost estimates to confirm repairs in any 12‑month period do not exceed 10% of replacement cost — § 17.48.040.
  • If the structure was destroyed/damaged, calculate replacement value to see whether > 50% threshold applies — § 17.48.030(B).
  • Check whether HCD/RCM/RCC or other overlay rules provide a different path (HCD CUP) — see Monrovia Overlay Districts and § 17.14.030/§ 17.16.050.
  • If adding an ADU or converting space, confirm the requirement that all structures be brought into compliance “to extent reasonable and feasible” (§ 17.48.030(C)) and consult Monrovia ADUs and California ADU law.
  • If applying to alter a use in a commercial corridor, check applicable parking rules and whether added parking will be required — link to Monrovia Parking.

Risks & Ambiguities

Issue Why it matters What to verify
Abandonment clock (180 days) If vacancy exceeds 180 days, nonconforming right is lost and any later use must conform — costly if you expected to resume the use Verify continuous operation records, business licenses, tax filings, and Council/DRC records; check both § 17.48.020(F) and § 17.48.030(F).
Damage >50% reconstruction test Rebuilding nonconforming structure after major loss is restricted; residential exception has caveats Confirm appraised replacement value, insurance claims, and whether the residential exception applies; see § 17.48.030(B).
“Equally appropriate” DRC finding Subjective: DRC can impose conditions or deny change to another nonconforming use Prepare comparative land‑use analysis, neighborhood impact mitigation, and municipal DRC precedent; see § 17.48.020(D) and § 17.52.030.
HCD / corridor exceptions HCD permits limited expansion by CUP — but only under supporting findings Request clarity from Planning staff and cite § 17.14.030 and § 17.16.050(D); verify which land‑use plan (General Plan Figure 1) applies.
ADU interplay with nonconformity Adding an ADU can trigger review and “bring into conformity” requirements for other structures Confirm whether conformity required is limited to building & safety compliance or returns the site to full zoning compliance; cite § 17.48.030(C) and check ADU chapters.
Wireless facility amortization Specific amortization timetable and 10‑year conformity requirement — subject to appeal For wireless sites consult § 17.48.070 and Chapter 17.46; appeal info and City Council discretion are provided in the code.

Plain-English Summary

Monrovia lets legally established nonconforming uses and structures keep operating, but you cannot make them worse: no enlargements, no relocations, limited repairs, and long gaps or destruction can eliminate your legal right. Major exceptions (HCD, corridor plans, wireless amortization, or density‑change approvals) exist but require DRC/CUP or Commission review and often recorded covenants. Key thresholds to remember: repairs capped at 10% of replacement cost per year, reconstruction restricted if damage exceeds 50%, and 180 days continuous vacancy generally ends nonconforming rights.

Source References

  • Monrovia Zoning — Chapter 17.48 (Nonconforming Uses & Structures): § 17.48.010 – § 17.48.070.
  • Repairs & maintenance rule: § 17.48.040 (10% rule).
  • Reconstruction / >50% destruction: § 17.48.030(B).
  • Abandonment / vacancy: § 17.48.020(F) and § 17.48.030(F).
  • Wireless telecommunication amortization and special rules: § 17.48.070 and Chapter 17.46.
  • HCD / West Huntington corridor nonconforming expansions: § 17.14.030; West Huntington rules § 17.16.050; special references table § 17.08.020.
  • RF (Residential Foothill) development standards: § 17.12.010.
  • RM / RH multi‑family standards, setbacks, FAR: Chapter 17.12 / § 17.12.030 and related tables referenced in Title 17.
  • Administration & approvals (DRC, CUP, variances, minor exceptions): Chapter 17.52 (notably § 17.52.030, § 17.52.110) — DRC powers and exception rules.
  • Monrovia ADU policy and state ADU interplay (background guidance referenced by City): Monrovia ADU chapter and state guidance — see Monrovia ADUs and California ADU law.
  • Monrovia Development Standards / parking references: City parking chapter § 17.24 and West Huntington references § 17.16.050; see Monrovia Parking and Monrovia Development Standards.

(If you need scanned PDF images or a parcel‑specific read of permits/recorded covenants, request that and I’ll list the records to pull. Verify with the City for final, parcel‑level determinations.)

Sources

Retrieved passages

  • Monrovia Zoning Code (§ 17.08.020) High relevance
  • Monrovia Zoning Code (§ 17.48.030) High relevance
  • Monrovia Zoning Code (Chapter 17.52) High relevance
  • Monrovia Zoning Code (§ 17.48.050) High relevance
  • Monrovia Zoning Code (§ 17.46.090.) Medium relevance
  • Monrovia Zoning Code (§ 17.52.200) Medium relevance
  • CFC § 5 (§ 5) Medium relevance
  • Monrovia Zoning Code (title to) Medium relevance
  • Monrovia Zoning Code (§ 17.48.020) High relevance
  • Monrovia Zoning Code (§ 16.08.135) High relevance
  • Monrovia Zoning Code (§ 17.44.105) Medium relevance
  • Monrovia Zoning Code (section shall) Medium relevance
  • Monrovia Zoning Code (§ 17.16.050) Medium relevance
  • Monrovia Zoning Code (§ 17.44.025) Medium relevance
  • CBC § 66314 (§ 66314) Medium relevance
  • Monrovia Zoning Code Medium relevance
  • Monrovia Zoning Code (§ 17.52.100) Medium relevance
  • Monrovia Zoning Code (§ 66333) Medium relevance
  • Monrovia Zoning Code (Section 6409) Medium relevance
  • Monrovia Zoning Code (§ 17.44.103.) Medium relevance
  • Monrovia Zoning Code Medium relevance
  • Monrovia Zoning Code (§ 17.24.010) Medium relevance
  • Monrovia Zoning Code Medium relevance

Cited sections

Frequently asked questions

Can a nonconforming use be expanded in Monrovia?

Generally no — a nonconforming use “may not be enlarged, extended, moved or altered” except where the code specifically allows it. A change to another nonconforming use is possible only if the Development Review Committee finds the new use is equally or more appropriate and imposes conditions as needed (§ 17.48.020(D)).

What happens if my nonconforming building is damaged in a fire?

If the nonconforming structure is destroyed by more than 50% of its reasonable replacement value, it generally cannot be reconstructed as a nonconforming building; there is a limited residential exception where reconstruction in a residential zone may be allowed but must meet building and safety regulations and be reviewed by the DRC (§ 17.48.030(B)).

How long can a nonconforming use sit vacant before it loses its status?

Continuous vacancy or discontinuation of the nonconforming use for 180 days (six months) typically causes the right to continue the nonconforming use to terminate; subsequent use must conform to district regulations (§ 17.48.020(F)).

Can I repair or renovate a nonconforming building?

Yes — routine maintenance and repairs are allowed, including replacement of non‑bearing walls, fixtures, wiring and plumbing — but the value of repair/replacement cannot exceed 10% of the replacement cost of the whole structure in any 12‑month period, and you cannot increase square footage via these repairs (§ 17.48.040).

If my use becomes nonconforming because zoning density changed, can I still alter the structure?

Monrovia allows limited enlargement, extension or reconstruction where a lawful use becomes nonconforming solely due to a change in density — subject to DRC approval, a site plan review, and a recorded covenant describing the structures approved for work (§ 17.48.050).

What special rules exist downtown or on Huntington Drive?

The HCD (Historic Commercial Downtown) and Retail Corridor sections include special provisions: HCD may allow expansion of nonconforming uses by conditional use permit where findings are met (§ 17.14.030) and the West Huntington rules (e.g., § 17.16.050) provide corridor‑specific nonconforming expansion provisions for RCM/RCC. Verify the applicable plan area (Figure 1 in the General Plan) before assuming an expansion path.

If I add an ADU, will that force me to fix other zoning nonconformities?

Adding an ADU on multi‑family property triggers a clause that “all structures on the property shall meet building and safety regulations” and that existing structures be brought into conformity “to the extent reasonable and feasible” as determined by the Committee or Commission (§ 17.48.030(C)). Consult the City ADU rules and state ADU law for limits on conditioning ADU approvals. Link: Monrovia ADUs and California ADU law.

Do wireless telecom sites have different nonconforming rules?

Yes. A wireless facility lawfully constructed before the Chapter 17.46 standards became effective and that is now nonconforming is treated as a nonconforming structure but must generally be brought into conformity within 10 years; abandonment rules and appeals use a distinct timetable and procedures (§ 17.48.070 and Chapter 17.46).

Who makes the final call when I propose a change to a nonconforming use?

The Development Review Committee (DRC) is the first reviewing body for changes allowed under § 17.48.020(D); for larger or contested applications the Planning Commission or City Council may be involved, and appeals follow the administrative chapters in Title 17 (see Chapter 17.52).

Where are the setbacks and dimensional rules I must meet if a nonconforming structure is reconstructed?

Setbacks and dimensional standards are in the residential and district chapters (for example § 17.12.010 for RF and § 17.12.030 for RM/RH multi‑family standards); any reconstruction that is permitted must comply with the district standards in addition to the nonconforming chapter’s limits (§ 17.48.030). See Monrovia Development Standards.

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