Rooftop Grease Containment: What Bay Area Landlords Are Now Requiring
Property managers across Contra Costa, Alameda, and San Francisco counties are now writing grease containment into commercial leases. Here is what the requirements look like.
Five years ago, rooftop grease was the landlord's problem. Today, it is almost always the tenant's — written into the lease, with photo documentation required at every cleaning, and a clearly assigned cost of remediation if the roof membrane is damaged. This article covers what changed, what the new lease language looks like in the Bay Area, and what 'containment' actually means in NFPA 96 terms.
What changed
Bay Area property managers got tired of paying for roof membrane replacement caused by grease overflow from poorly maintained exhaust fans. A single grease-saturated TPO or single-ply roof can cost $40,000 to $120,000 to replace on a typical strip-center footprint, and most commercial property insurance carriers exclude gradual damage — meaning the landlord eats the cost.
Two things shifted starting around 2021: roof manufacturers began voiding warranties for grease contamination, and commercial insurers began excluding 'grease-related membrane degradation' as a named peril. Landlords responded by pushing the entire risk down to the tenant in the lease.
Typical new lease language
We see the same clauses showing up in leases from Walnut Creek to South San Francisco, Concord to Mountain View. The exact wording varies but the substance is consistent:
- Containment device required at every grease-bearing exhaust fan
- Containment must be UL-listed and sized to the fan's exhaust volume
- Containment must be inspected and serviced at the same cadence as the hood cleaning
- Photo of the containment device required on every service report submitted to the landlord
- Tenant responsible for any roof damage attributed to grease, including consequential damage to adjacent tenant spaces
- Landlord may inspect the roof with 24 hours' written notice
- Failure to maintain containment is a curable default with 10 days' notice, after which the landlord may install and bill the tenant at cost plus 15%
If you are renewing a lease right now in Contra Costa or Alameda County, expect to see at least four of these seven clauses. If you are signing a new lease, expect all seven.
What 'containment' actually means
A proper containment device is a UL-listed grease box installed under or around the fan, sized to the fan's CFM rating, with absorbent media inside that captures liquid grease before it reaches the roof membrane. The media is replaced at every cleaning and disposed of as grease waste, not as ordinary trash.
A pizza pan, a roll of paper towels, an old fryer basket, or a kitty-litter box duct-taped to the curb is not containment. We have removed all four of those from Bay Area rooftops in the last 12 months. None of them satisfy lease language and none of them satisfy NFPA 96.
The three real containment options
- Drop-in absorbent box under a hinged fan — most common retrofit, $250–$600 installed
- Surround-style stainless containment that catches drips from the fan curb — better for high-volume fryer or charbroiler fans, $600–$1,200
- Grease-diverter system that pipes captured grease to a roof-edge collection container — for very high-volume operations or sensitive roof systems, $1,500+
All three need media replacement on the same cadence as your hood cleaning. The box does not work if no one is changing the pad.
Getting compliant before the inspection
If you are signing a new lease or renewing an old one, get the containment installed and photographed before the landlord's walk-through. It is one of the few compliance items that takes under an hour and costs less than a single rooftop repair callout.
If you already have containment but you are not sure it is documented, ask your cleaning vendor to add a containment-condition photo and a media-replacement note to every report going forward. Send the landlord a copy of the next report unprompted — it puts you in front of any future dispute.
Who pays when there is already damage
If the roof is already grease-stained when you take the space, get it in writing — photographed, dated, and attached to the lease as an exhibit. Without that exhibit, the default assumption in most California commercial leases is that any grease damage discovered during your tenancy is yours, regardless of when it actually occurred.
A 15-minute roof walk with the landlord on day one of the lease has saved Bay Area operators six-figure repair bills more than once.