Menlo Park is mid-update on both ADUs and SB 9, which cuts both ways. Some local limits may loosen, but an application filed under one set of rules can get caught in the change. If you're planning a project, ask the city which version applies on the day you submit. For rentals, remember relocation money is owed on every no-fault notice here, not just some.
Adding an ADU
In Menlo Park
On June 9, 2026, the City Council adopted an updated ADU ordinance, effective July 10.[1]
State law, everywhere in California
A city has 60 days to approve or deny a complete ADU or junior ADU (JADU) permit application.[2]
Lot coverage, floor area ratio, and front setback rules can't be used to block an ADU of at least 800 square feet with four-foot side and rear setbacks.[2]
A city can't set a height limit below 16 feet for a detached ADU, or below 18 feet within a half mile of a major transit stop or high-quality transit corridor. Attached ADUs can go to 25 feet or the main home's zoning height, whichever is lower.[2]
A JADU is up to 500 square feet of interior space inside the main home. Owner occupancy can't be required for an ADU, but it is required for a JADU that shares a bathroom with the main home.[2]
No impact fees on an ADU of 750 square feet or less. Above that, fees have to be proportional to the main home.[2]
On a lot with an existing apartment building, state law allows up to eight detached ADUs (never more than the number of existing units), plus conversions of non-living space.[2]
Lot splits and second homes
In Menlo Park
SB 9 applies in the R-E-S, R-E, R-1-S, R-1-S (FG), R-1-U, and R-1-U (LM) zones.[3]
The city is updating its SB 9 ordinance (Municipal Code Chapters 15.31 and 16.77) for consistency with SB 450. The Planning Commission held a study session on June 8, 2026.[3]
The city states that each lot from a split has to be at least 1,200 square feet, with neither lot less than 40% of the original.[3]
In a July 2024 letter to Menlo Park, HCD said a city can't require park in-lieu (Quimby) fees as a condition of approving an SB 9 lot split.[4]
State law (SB 9)
SB 9 applies to lots zoned single-family. It allows two primary homes on one lot, a split into two lots, or both, with staff-level approval and no public hearing.[4]
Local rules can't stop two homes of at least 800 square feet each, or a split into two lots of at least 1,200 square feet. Side and rear setbacks are capped at four feet.[4]
Parking is capped at one space per unit, and none can be required within a half mile walk of a high-quality transit corridor or major transit stop, or within a block of a car-share vehicle.[4]
To split a lot, you sign an affidavit that you intend to live in one of the units as your main home for at least three years. Any rental has to be for more than 30 days.[4]
SB 9 doesn't apply if the project would demolish or alter rent-restricted housing, rent-controlled housing, or housing a tenant has lived in during the last three years. It also excludes historic properties, lots with an Ellis Act withdrawal in the last 15 years, lots already created by an SB 9 split, and lots next to one the same owner split.[4]
The ceiling is four units total. After a split, the city has to allow two units on each new lot. The city must decide on a complete application within 60 days.[4]
Rent control and AB 1482
In Menlo Park
State law (AB 1482)
Under the Tenant Protection Act (AB 1482), rent can't go up more than 5% plus the change in the cost of living, or 10%, whichever is lower, in a 12-month period.[6]
After a tenant has lived in a unit for 12 months, the landlord needs a listed reason to end the tenancy, either at-fault (like nonpayment) or no-fault (like owner move-in or a substantial remodel).[6]
Exempt: units with a certificate of occupancy issued in the last 15 years (a rolling date), single-family homes not owned by a corporation or REIT, a duplex where the owner lives in the other unit, and units already under a stricter local rent control law.[6]
What is your Menlo Park home worth, and what could it become?
I spent my career on the investment side, helping operate more than 7,000 units. I'll give you a valuation built from recent sales, and a straight read on what your lot allows: an ADU, a split, or neither.
Menlo Park questions, answered
Did Menlo Park change its ADU rules recently?+
Yes. The City Council adopted an updated ADU ordinance on June 9, 2026, effective July 10.[1]
Which Menlo Park zones allow SB 9?+
R-E-S, R-E, R-1-S, R-1-S (FG), R-1-U, and R-1-U (LM).[3]
Do Menlo Park landlords owe relocation on a no-fault eviction?+
Yes. One month's rent for all tenants, or up to three to four months if the tenant qualifies under the city's Tenant Relocation Assistance ordinance.[5]
- [1]City of Menlo Park, “Accessory dwelling units”
- [2]California Department of Housing and Community Development (HCD), “ADU Handbook (March 2026 update)”
- [3]City of Menlo Park, “SB 9 Projects”
- [4]California Department of Housing and Community Development (HCD), “Housing Law Fact Sheet: Duplexes and Lot Splits (SB 9), April 2026”
- [5]City of Menlo Park, “Rent limits and just cause eviction protections”
- [6]California Attorney General, “Landlord-Tenant Issues: Tenant Protection Act”
Official Menlo Park pages
This page is general information, not legal or tax advice. Rules change, and cities amend their codes after state reviews. Confirm current requirements with the city and a qualified professional before you buy, build, or change a tenancy. Erica Walters, REALTOR®, CalDRE# 02239622, Compass.