What happens if you skip the permit (and you need one)
- Stop-work orders and fines: City can issue a cease-and-desist order and fine $100–$500 per day of violation; unpermitted construction is also a code enforcement case that can carry liens.
- Lender and insurance refusal: Unpermitted ADU construction will be flagged in any title search; lenders will refuse to refinance the property, and homeowners' insurance may deny claims related to the unpermitted unit.
- Forced removal and 'undo' cost: If the ADU is discovered during resale, refinance, or code enforcement, the City can require demolition of non-compliant portions or the entire unit — easily $15,000–$50,000 in removal and rebuilding to code.
- Property sale disaster: California's Transfer Disclosure Statement (TDS) requires disclosure of unpermitted improvements; buyers can sue for rescission or damages, and title insurance will not cover the unpermitted ADU.
Hollister ADU permits — the key details
State law, not city choice, governs Hollister ADUs. California Government Code § 65852.22 (as amended by AB 68 and AB 881) requires cities to approve detached ADUs up to 800 sq ft on single-family or multifamily lots, garage conversions, junior ADUs (no separate kitchen, max 500 sq ft), and above-garage units — with minimal local discretion. Hollister adopted a local ADU ordinance in 2017 but has been effectively overridden by subsequent state bills. The practical upshot: if your project meets the state definition and basic code (egress windows per IRC R310.1, water/sewer service, legal access), Hollister must issue the permit. The City cannot impose a discretionary design-review hearing, cannot require owner-occupancy of the primary residence, and cannot impose parking requirements that exceed state limits (which are minimal for ADUs). The 60-day shot clock under Government Code § 65852.22(d) applies: if your application is complete and the City doesn't issue a decision within 60 days, the application is deemed approved, and you can move forward. That clock stops only if you request a continuance or the City issues a notice of incomplete application (but only once per application cycle). For Hollister specifically, check with the Building Department to confirm whether the City has adopted SB 9 pre-approved ADU plans — some Bay Area cities now fast-track SB 9 designs to 3–4 weeks.
Setbacks, lot size, and local amendments matter most. While state law strips away owner-occupancy and parking requirements, it does NOT eliminate setback rules. Hollister's local code (likely Title 16 or equivalent) still requires setbacks from property lines, typically 5–10 feet for detached ADUs depending on zone. If your lot is small (under 5,000 sq ft) or is in a tight urban infill zone, the detached ADU may not fit the required setbacks — in which case you'd pivot to a garage conversion, junior ADU, or above-garage unit instead. Confirm with the Building Department whether Hollister has adopted 'by-right' ADU approval for certain zones (many cities now carve out ADU-friendly overlay districts). Also verify whether Hollister requires a survey of the legal lot lines and setback calculation — some jurisdictions require a civil engineer or surveyor sign-off if setback is tight. Parking: state law now waives parking requirements for ADUs in certain circumstances (e.g., if the property is within a half-mile of transit, or in a neighborhood parking-shortage area), but Hollister may still require one off-street space if local code was more restrictive before SB 9. This is a detail to confirm early in conversation with the Building Department.
Utility connections and metering are a common stumbling block. Your ADU must have separate water, sewer (or septic if rural), and electrical service from the primary residence — or a separately metered connection if shared infrastructure is used. This is a building code requirement (IRC R303.1 for separate utilities on new construction) and also a municipal-services requirement in Hollister. If you're converting an existing garage, existing sewer and water lines may run to the main house; you'll need a licensed plumber to run new lines from the main meter/cleanout to the ADU, or install a sub-meter if the City allows shared lines. Electrical is even more critical: you cannot run a single electrical panel for both the main house and ADU; the ADU must have its own service entrance and panel, sized to the unit's load. A licensed electrician and the City's electrical inspector will verify this during rough and final inspections. Septic systems: if your property is on septic (not public sewer), an ADU typically requires system upsizing or a separate system — this can add $5,000–$15,000 and requires an engineer's report. Confirm your lot's sewer/water status with the City before you spend on design.
Egress windows and bedroom count drive code compliance. If your ADU has a bedroom, it must have an emergency escape window per IRC R310.1 — a window at least 5.7 sq ft of openable area (3 ft wide, 4 ft tall minimum), with a sill height no more than 44 inches from the floor. This is not optional. Many garage conversions and above-garage ADUs fail plan review because the egress window is either missing, too small, or has a sill that's too high. If your detached ADU or conversion is a studio (no bedroom), you don't need an egress window in the living space, but if you have a bedroom, you must have one in that room. Some homeowners try to avoid the egress-window cost by designating the bedroom as a 'den' or 'office' — the City will flag this if the space is sized and located like a bedroom (has a closet, is in a quiet part of the unit, has a lock on the door). Be honest about bedrooms in your application; the inspector will count them. Also, if your ADU will be rented, California residential code (which Hollister enforces) may impose additional fire-safety requirements: sprinklers if the unit is over a certain size (typically 750 sq ft in some jurisdictions), or fire-rated doors and walls. Confirm with the City whether sprinklers are triggered by the ADU's square footage alone, or by the combined sq ft of the ADU + primary residence.
Timeline, fees, and owner-builder rules. Hollister aims for a 60-day decision under state law, but plan review can take 2–4 weeks if the City has a backlog. Total timeline is typically 8–12 weeks from complete application to building permit issuance, then another 4–8 weeks for construction and final inspection (depending on scope). Permit fees in Hollister are typically $2,500–$8,000 for an ADU (building permit, plan review, and impact fees combined); add $500–$1,500 for electrical and plumbing permits if separate. Owner-builder is allowed under California Business & Professions Code § 7044 for single-family residences, but you cannot pull the permit as owner-builder for an ADU if you are renting it out — an ADU is considered multi-unit housing by some interpretations. Confirm with the Hollister Building Department whether owner-builder is allowed for your specific project. If you go owner-builder, you will do your own labor for framing, drywall, painting, and rough carpentry, but you MUST hire a licensed electrician (C10 license) for electrical work, a licensed plumber (C36 license) for plumbing, and likely a licensed HVAC contractor (C20 license) for any furnace or AC. The Building Department will require you to post a Notice of Non-Licensed Contractor and obtain a Home Improvement Contractor license if the project cost exceeds $500. It's often simpler to hire a licensed general contractor and let them pull the permit; they absorb the liability and expedite plan review. Budget accordingly: ADU total cost (site work, construction, permits, utilities, inspections) typically ranges from $80,000–$200,000 depending on whether you're doing a new detached unit, conversion, or above-garage unit.
Three Hollister accessory dwelling unit (adu) scenarios
California state law overrides Hollister local zoning — how the 60-day shot clock works
Hollister adopted a local ADU ordinance in 2017, but it has been effectively superseded by three state bills: AB 68 (2018), AB 881 (2020), and SB 9 (2021). These bills amended Government Code § 65852.22 to strip away local discretion and impose a strict 'by-right' approval process for qualifying ADUs. The key provisions: (1) Detached ADUs up to 800 sq ft must be approved on single-family lots, (2) Attached ADUs (garage conversions, above-garage) up to 800 sq ft must be approved, (3) Junior ADUs (no separate kitchen, max 500 sq ft) must be approved, (4) Owner-occupancy requirements for the primary residence are waived, (5) Parking requirements are waived in certain circumstances (within half-mile of transit, or in areas with unmet parking demand), and (6) The City has 60 days from a complete application to issue a decision — if it misses that deadline without your consent, your application is deemed approved. This is not a discretionary hearing or design-review process; Hollister's role is ministerial — check the application against code, approve or deny on code grounds only. The shot clock is critical: if your application is deemed complete on day 1, the clock starts. The City can stop the clock once (for an incomplete-application notice) if there are material gaps in your plans. But if the City re-notices incompleteness and you resubmit, the clock restarts. If the City issues a complete-application notice and then takes 61 days without a decision, you can proceed as if the permit was approved (though it's wise to formally request deemed approval in writing and escalate to the City Manager if the Building Department doesn't cooperate).
What constitutes a 'complete application' in Hollister is the flex point. The City's application checklist typically requires: site plan (showing lot lines, setbacks, parking, utilities), floor plan, electrical one-line diagram, plumbing isometric, foundation detail, roof plan, exterior elevations, and if the lot is tight, a survey or civil engineer's setback verification. If your submission lacks, say, a structural engineer's stamp on foundation details (required for above-garage ADUs), the City can issue an incomplete notice. The key: get the application checklist from the Building Department in advance, fill it completely, and deliver in person or via the City's permit portal (if available) so you have proof of completeness. This prevents disputes about when the 60-day clock starts.
Hollister's local code can still impose restrictions on setbacks, lot coverage, parking (if not waived by state law), and design compatibility in historic zones — but these must be applied equally to ADUs as to primary residences, and cannot be used as a pretext to deny an ADU that meets state criteria. For example, Hollister cannot require a 15-foot setback for ADUs while allowing 5 feet for primary residences. If the City's local code conflicts with state law, state law wins. This is a major shift from pre-2018 practice, when cities could zone ADUs out of existence.
Utility connections and metering: where permits stall and how to avoid it
Separate utility connections are required for all ADUs under both building code (IRC) and municipal-services law, but 'separate' can be interpreted as either (1) entirely independent lines and meters, or (2) shared lines with submeter separation at the meter/cleanout level. Hollister's local code and the City's water/sewer/electric departments will define what 'separate' means for your lot. For water: if the main house and ADU share a line, you can install a submeter at the point where the line branches off, and each unit gets its own meter reading. For sewer: same principle — a submeter (cleanout) at the branch point. For electricity: the ADU must have its own service entrance and panel, fed from its own meter on the main electrical service. These are not negotiable items; the City's plan reviewer will flag missing utility separation, and the utility departments (water, sewer, electric) will not sign off on the project during final inspection if separation is not shown.
The common plan-review stall: the applicant draws plans with the ADU 'sharing utilities' with the main house (a single line feeding both), and the City rejects it. The applicant then hires a licensed plumber and electrician to draw utility plans, adding cost and timeline. Avoid this by hiring a licensed plumber and electrician to design the utility layout BEFORE you submit the building permit application. A consultation with them (2–3 hours) costs $300–$500 and saves you a plan-review rejection. Ask them: 'If I build an ADU here, what are the separate water, sewer, and electrical connections? Will we need new meters, new service line, new panel?' They'll give you a clear answer and can sketch the layout for your architect to incorporate into the building plans.
Rural septic scenario: if your Hollister property is on septic (not connected to public sewer), an ADU adds plumbing load to the existing system. You'll need an engineer to evaluate the septic tank and drainfield capacity. A 1,500-gallon tank serving a 3-bedroom primary residence may be adequate, but adding a 1-bedroom ADU (2+ occupants) may exceed its design load. Upsizing or installing a second system can add $8,000–$15,000. This must be resolved during plan review; the Building Department will require a septic engineer's report stamped by a California-licensed environmental systems designer. Do not assume a 50-year-old septic can handle an ADU without professional evaluation.
Hollister City Hall, 375 Fifth Street, Hollister, CA 95023 (verify current address and permit counter location with City website)
Phone: (831) 636-4000 (main City line — ask for Building and Safety Department or Building Permits) | Hollister likely uses an online permit portal; search 'City of Hollister building permit' or visit hollisterCA.gov to confirm portal URL and e-file options
Monday–Friday, 8:00 AM–5:00 PM (typical, verify with City website or phone)
Common questions
Do I need owner-occupancy (living in the main house) to get an ADU permit in Hollister?
No. California Government Code § 65852.22, as amended by AB 68, waived the owner-occupancy requirement for ADUs statewide. You can build an ADU and rent both the main house and ADU, or live in the ADU and rent the main house, or rent both. Hollister cannot impose an owner-occupancy condition. This is a major change from pre-2018 practice.
Can Hollister require parking for my ADU?
Not always. AB 881 (2020) waived ADU parking requirements in many cases: within half-mile of a major transit stop, within a half-mile of a job center, in a 'parking-constrained' neighborhood, or if the lot is in a transit village or downtown infill area. Hollister's local code may define these zones. Downtown lots (historic zone, near the downtown square) are likely parking-exempt. Suburban lots may still require one space. Contact the Building Department early to confirm whether your specific lot qualifies for a parking waiver.
What is the difference between a junior ADU and a standard ADU?
A junior ADU has no separate kitchen (only a kitchenette with a sink, and no stove or oven) and is capped at 500 sq ft. A standard ADU has a full kitchen (sink, range/cooktop, refrigerator) and is capped at 800 sq ft (detached) or 800 sq ft (attached). Junior ADUs are slightly faster to permit because they're smaller and the no-kitchen constraint is easier to verify. Choose junior ADU only if you can live with a kitchenette; otherwise, go standard.
Do I need a survey to show setbacks on my ADU site plan?
If the lot is well-defined and large, a visual site plan with approximate distances may be accepted. But if setbacks are tight (e.g., detached ADU on a 5,000-sq-ft lot) or the lot has an irregular shape, the Building Department will likely require a civil engineer's or surveyor's site plan with legal lot lines, dimensions, and setback distances stamped and signed. Budget $400–$800 for a survey and $500–$1,500 for a civil engineer's site plan if you're unsure — it's cheaper than a plan-review rejection.
If the City misses the 60-day deadline, is my permit automatically approved?
Yes, in theory. Government Code § 65852.22(d) states that if the City doesn't issue a decision within 60 days of a complete application (and you haven't requested a continuance), the application is deemed approved. However, Hollister must still issue a formal permit document before you can pull a building permit and start construction. If the City is slow, send a letter to the Building Director citing the shot clock, formally request deemed approval, and copy the City Manager. This escalates pressure; most cities will issue a permit rather than litigate deemed approval. You can also file a writ of mandate in superior court, but that's expensive — use it as a last resort.
Can I use an owner-builder license to pull the ADU permit myself in Hollister?
Yes, under California Business & Professions Code § 7044, if the ADU is for a single-family residence and you are not hiring it as a rental from the start. However, you must still hire licensed contractors for electrical (C10), plumbing (C36), HVAC (C20), and structural work (PE-stamped). If you are renting the ADU immediately upon completion, the Building Department may argue it is not a 'single-family residence' and deny owner-builder status. Confirm with the City before you commit to owner-builder. Also note: if the project cost exceeds $500, you'll need to obtain a Home Improvement Contractor license and post a Notice of Non-Licensed Contractor. It's often simpler to hire a licensed GC.
How much will the permit cost for an ADU in Hollister?
Building permit fees typically range $2,500–$8,000 for an ADU, depending on size and complexity. Hollister calculates permit fees as a percentage of project valuation (often 1.5–2% for residential) plus plan-review and inspection fees ($500–$1,500). Electrical and plumbing permits are separate: $300–$800 each. Impact fees (sewer, water connection) add another $1,000–$3,000 if the property is not already served by adequate capacity. Request a fee estimate from the Building Department when you request the application checklist.
If I'm in Hollister's historic district, can the City deny my ADU for design reasons?
No, but design review is still triggered. State law requires the City to approve qualifying ADUs 'ministerially' — meaning the City cannot impose discretionary design conditions beyond what applies to primary residences. However, Hollister's historic-overlay code may require a design-review consistency statement for visible exterior changes. This is advisory and cannot be used as a pretext to deny an ADU that meets setback, height, and code standards. Interior historic features (wood beams, original foundations) do not apply to new ADU construction. Focus on making the ADU compliant with code; historic design is secondary.
What inspections will the City require for my ADU?
Full building inspections: (1) foundation/footing, (2) framing, (3) rough electrical/plumbing/HVAC, (4) insulation, (5) drywall, (6) final building, (7) final electrical, (8) final plumbing, (9) final mechanical (HVAC). If the ADU includes a sprinkler system (triggered by total square footage over a threshold), (10) fire-protection final. The Planning Department may also require a final sign-off to confirm the ADU is legally a 'unit' on the parcel. Schedule each inspection 24 hours before work is ready; Hollister's Building Department typically inspects within 1–3 days. Budget 8–10 weeks from framing start to final occupancy.
I want to build an ADU on my property, but I'm worried about property-line disputes with my neighbor. What do I do?
Get a professional survey before you apply for a permit. A survey confirms your legal lot lines and shows exact setback distances from the property line to your proposed ADU. This costs $400–$800 but eliminates neighbor disputes and prevents a plan-review rejection due to unclear setbacks. Many Hollister Building Department staff will accept a survey-stamped site plan without requiring a separate civil engineer's certification. Once you have the survey, you have legal proof of setback compliance, and your neighbor cannot later claim the ADU is on their land.