ADU Laws · 2026
Monterey County ADU Fees: What You Actually Pay (2026)
The single fact that changes the fee picture the most in Monterey County: ADUs under 750 sq ft are exempt from impact fees under state law. That covers most of our smaller and mid-size models outright. Above that size, fees are calculated proportionally, and Monterey County sweetens the process further with three free pre-designed plans (515, 749, and 1,200 sq ft) that can speed up plan check.
The short version: Units under 750 sq ft skip impact fees entirely. Units at or above that size pay fees proportional to the main house. The county’s free pre-designed plans (up to 1,200 sq ft, in two exterior styles) can shorten review. We build the exact fee picture into your feasibility study so there’s no guessing.
The state impact fee waiver, and why it matters most here
California law waives ADU impact fees below 750 sq ft outright, and requires fees on larger units to be charged in proportion to the size of the primary home rather than as a flat new-construction rate. In Monterey County, this waiver is the single biggest fee lever homeowners have:
| Unit size | Impact fee treatment |
|---|---|
| Under 750 sq ft | Waived by state law |
| 750 sq ft and up | Charged proportionally to the primary residence, not a flat fee |
| County’s 1,200 sq ft pre-designed plan | Falls in the proportional-fee tier |
| County’s 515 and 749 sq ft pre-designed plans | Fall under the waiver |
If keeping impact fees off the table matters to your budget, a model in the 405 to 660 sq ft range keeps you comfortably under the 750 sq ft line.
What “fees” actually covers
Homeowners researching this often lump several different charges together. In Monterey County, the categories that can apply are:
- Building permit and plan-check fees: set by the county (or your city, if you’re inside Salinas, Marina, Monterey, Pacific Grove, or Carmel city limits) and scaled to project valuation.
- Impact fees: school, park, and traffic fees; waived under 750 sq ft as above.
- Utility connection fees: water meter and sewer connection charges vary by district and whether you’re on a public system or septic.
- Coastal Administrative Permit fee: applies only if your parcel is in the Coastal Zone. See our coastal zone guide for the full picture.
We never quote a specific dollar figure from memory for permit or connection fees, because they genuinely vary by parcel and by which agency issues them. That’s exactly what the feasibility study confirms for your address before you sign anything.
Septic lots carry a real cost consideration
If your property is on septic rather than a sewer connection, know this going in: lots under roughly 1.25 acres on septic usually need an upgraded, alternative septic system to add an ADU. That’s a real cost that shows up before you get to building permit fees at all, and it’s one of the first things we check on a septic lot during the feasibility study.
How Framework First’s pricing handles all of this
Every Framework First ADU price includes a permitting budget alongside plans, foundation, the factory build, delivery, hookups, appliances, and final inspection. Permit costs themselves are set by the county or your city, so we confirm the real number for your parcel in the feasibility study before it’s folded into your total. Our pricing runs $180,000 to $557,000 across 14 models from 405 to 1,200 sq ft, delivered in 4 to 9 months, with the home built roughly 97% in our Salinas factory before it’s crane-delivered to your lot. We’re family-owned, based since January 2021 (CSLB #1047146, MFG #1595931).
That means the fee picture above isn’t something you have to track separately. Once your feasibility study confirms your parcel’s specific fees, they’re built into your quoted price, not added on afterward.
Compare models and transparent pricing, or see the full 7-step process that gets you from first call to keys. When you’re ready, start with your city: Salinas, Marina, or Monterey.
Frequently asked questions
Are Monterey County ADU fees the same everywhere in the county?
No. Fees differ between unincorporated Monterey County and each city (Salinas, Marina, Monterey, Pacific Grove, Carmel), because permit and connection fees are set locally. State-level protections, like the under-750 sq ft impact fee waiver, apply everywhere in the county the same way. We confirm your specific parcel’s fees in the feasibility study.
Does the free pre-designed plan really save money?
It can speed up plan check, since the plan has already been through county review once. Whether it changes your fee total depends on your unit’s size relative to the 750 sq ft threshold, not the plan itself. We’ll walk you through whether a pre-designed footprint or one of our own models fits your lot and budget better.
Do I pay Monterey County fees separately from Framework First’s price?
Not as a separate line item after the fact. Framework First builds a permitting budget into your price, and we confirm the actual permit, plan-check, and connection fees for your parcel during the feasibility study before they’re folded into your contract number. What can sit outside that price is property-specific site work, like a septic system upgrade, which we still handle in-house as part of your build so the whole project stays with one builder.
What if my lot needs a Coastal Administrative Permit?
That’s a separate review layer for Coastal Zone parcels, on top of the standard ADU permit. It doesn’t remove your state-law protections, but it does add a step. We flag this immediately if your address falls in the Coastal Zone. Read more in our coastal zone guide.
Want your exact fee picture instead of a general range? Start a feasibility study and we’ll confirm what applies to your specific Monterey County parcel, then build it into your price.