Everything homeowners ask about building an ADU in Upland — answered with 2026 data.
Yes, ADUs are allowed in Building-permit-only ADUs (§ 17.37.040(A)): any lot in a residential or mixed-use zone. ADU-permit ADUs (§ 17.37.040(B)): lots zoned for single-family or multifamily residential use. JADUs: single-family-zoned lots only (§ 17.37.050(A)). No minimum lot size. in Upland, CA. The maximum size for a detached ADU is Building permit only: one detached new ADU of 800 sq ft or less (§ 17.37.040(A)(2)). ADU permit: 850 sq ft for a studio/1-bedroom, 1,000 sq ft for 2+ bedrooms (§ 17.37.060(A)); no lot-coverage, FAR, front-setback or open-space rule may push the ADU below 800 sq ft. Attached ADUs can be up to 850 sq ft. Upland has an ADU-friendliness score of 6/10. Check our full Upland ADU rules page for complete zoning details.
ADU construction in Upland typically costs $175,000-$350,000. The cost per square foot averages $180-$350. Garage conversions are more affordable at $75,000-$150,000, while prefab ADUs cost $120,000-$250,000. Permit fees add ADU permit fee set by Council resolution (§ 17.37.040(B)); the city's April 2023 guidebook listed $810, plus building permit/plan check typically $3,000-$4,000 and a $189 county fire letter. 2026 amounts not published online; confirm with Building & Safety, (909) 931-4110. to your budget. See our detailed Upland ADU cost guide.
Detached ADUs in Upland can be up to Building permit only: one detached new ADU of 800 sq ft or less. Attached ADUs are limited to 850 sq ft. Junior ADUs (JADUs) have a cap of 500 sq ft, entirely within the existing or proposed single-family house (an attached garage counts as inside the house); efficiency kitchen required (§ 17.37.030). Maximum height is Detached: 16 ft; 18 ft within 1/2-mile walking distance of a major transit stop or high-quality transit corridor (+2 ft, max 20 ft, to match the main roof pitch) or on a lot with a multistory multifamily building. Attached: 25 ft or the zone limit, whichever is lower, max 2 stories. Height is measured from existing grade to the peak (§ 17.37.050(B)). Detached ADU-permit units are one story only (§ 17.37.060(J)). You are allowed up to Single-family lot: one ADU plus one JADU. Multifamily lot: converted ADUs in non-livable space up to 25% of the existing units on a qualifying lot.
Rear setback: 4 ft minimum (§ 17.37.060(B)); none when the ADU is built in the same location and to the same dimensions as an existing structure. Side setback: 4 ft minimum; 15 ft on the street side of a corner lot, and corner lots must keep a clear vision triangle (§ 17.37.060(B)). Front setback: 25 ft for ADU-permit units (§ 17.37.060(B)(1)), but the front setback cannot be used to prevent an 800 sq ft ADU (§ 17.37.060(A)(3)); building-permit-only units have no city front-setback rule. Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
1 off-street space per ADU-permit ADU; tandem or in setback areas allowed; unenclosed spaces 9 x 19 ft, garage spaces 10 x 20 ft. Waived within 1/2 mile walking distance of public transit, in a historic district, for conversions, where on-street permits are not offered to the ADU, within one block of a car-share stop, or when filed with a new house. No replacement parking for a demolished or converted garage (§ 17.37.060(F)). JADUs need no space. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Not required for ADUs created on or after January 1, 2020 (§ 17.37.050(G)(1)); required for JADUs, with the owner living in the house or the JADU (§ 17.37.050(G)(2); Gov. Code 66333-66339). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Upland is typically 60 days from a complete application, deemed approved if the city does not act (§ 17.37.040(C)); the city's 2023 guidebook adds 15-21 working days for the San Bernardino County Fire residential fire letter. No current published averages. Plan check: Planning checks Chapter 17.37 (zoning, size, setbacks, design); Building & Safety checks the California Building/Residential Codes as amended by Ordinance 2004 (Nov 24, 2025); San Bernardino County Fire issues a residential fire letter ($189 in 2023). Sprinklers only if the main house has them (§ 17.37.050(C)). Applications go through the city's CSS online portal. Pre-approved plans availability: The city's Building & Safety Division publishes a Pre-approved ADU Plans page (last read July 2026); the number of plans, sizes and any plan fee could not be re-verified on Sept 20, 2026 because the city website was unreachable. A site-specific plot plan is still required. Confirm current availability with Building & Safety, (909) 931-4110.
Average ADU rental income in Upland: 1-bedroom units rent for $1,900-$2,250/month, 2-bedroom units for $2,250-$2,750/month. Short-term rentals: No. No ADU or JADU may be rented for a term shorter than 30 days, regardless of when it was built (§ 17.37.050(D)); the city regulates other short-term rentals separately through its Planning Division. Expected ROI: 7-12% gross rental yield (annual rent divided by build cost, before vacancy, taxes and financing).
The minimum lot size for an ADU in Upland is None. Lot-coverage caps apply to ADU-permit units: 35% in RS-15/RS-20, 40% in RS-10, 45% in RS-7.5 and B/R-MU, 50% in RS-4, each subject to the 800 sq ft floor (§ 17.37.060(C)); RM-10/RM-20/RM-30 lots must keep 100 sq ft private and 250 sq ft common open space per unit (§ 17.37.060(D)). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Upland, a garage conversion typically costs $75,000-$150,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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