Whether you're buying a home, planning an ADU, or adding on, one of the first things to check on a City of Los Angeles property is its methane designation. It decides whether methane testing and mitigation are part of your permit. The good news: the City publishes it for every parcel, for free, on ZIMAS.

How to Check Your Property on ZIMAS

1. Go to zimas.lacity.org and accept the terms of use.
2. Search your address (house number and street name) or your Assessor Parcel Number (APN).
3. Open the parcel information panel on the left side of the map once your parcel is selected.
4. Expand the "Additional" section and find the Methane Hazard Site line.
5. Read the result: Methane Zone, Methane Buffer Zone, or None.
6. Save the Parcel Profile Report (the printable PDF of the parcel's data). Your designer, consultant, and plan checker will all want it.

ZIMAS labels occasionally change when the City updates the site. If you don't see the methane line, look through the parcel's hazard and additional information sections, or ask your consultant to pull it for you.

What the Result Means

• Methane Zone: the higher-risk tier, generally over or close to oil fields, former wells, or natural seeps. New buildings must meet the City's methane requirements, and testing usually determines how much mitigation is needed.
• Methane Buffer Zone: the area surrounding a Methane Zone. New buildings must also comply, but for the same test result the Buffer Zone mitigation table generally requires less.
• None: the City's methane requirements for that parcel generally don't apply to your project.

Only City of Los Angeles Parcels Show Up This Way

ZIMAS covers properties within the City of Los Angeles. If your address is in a separate city such as Beverly Hills, Culver City, or Santa Monica, or in an unincorporated County area, ZIMAS isn't the right source; check with that jurisdiction's building department instead.

My Lot Is in a Zone. What Now?

1. Tell your designer immediately. The methane requirements affect slab and foundation details.
2. Decide whether to test. Testing sets your Site Design Level; skipping it means designing to the most stringent level. See Site Design Levels I through V explained.
3. Test before grading and before plans are finalized to avoid redesigns and the 30-day post-grading wait.
4. Budget for both. Testing is a few thousand dollars; mitigation depends on your result. See what methane testing costs.

Building an ADU? Read our ADU methane testing guide for the full step-by-step.

Buying a Property in a Methane Zone?

A methane designation isn't a reason to walk away. Thousands of homes and apartment buildings sit in these zones. It's a cost and schedule item for any future construction, so factor it in if you plan to add an ADU, rebuild, or expand.

Need a Second Opinion?

Send GeoTed your address and we'll confirm the designation and explain what it means for your project. GeoTed is led by a California Professional Geologist and Certified Engineering Geologist and is completing its City of Los Angeles testing agency approval. Contact GeoTed.

This article is general information, not site-specific engineering advice. Confirm requirements for your property with LADBS and a qualified professional.