Combined Gas, Smoke and CO Notice: One Sign Instead of Three
Lobby walls fill up fast. Smoke notice, CO notice, gas leak notice and soon the natural gas detector notice. The good news: HPD lets you combine them into one sign. Here's how that works and what to watch for.
The quick answer
In short: HPD allows one combined notice that covers smoke detectors, carbon monoxide detectors, natural gas detectors and the suspected gas leak steps. HPD publishes sample wording in 28 RCNY Section 12-12.1. The gas leak part must stay in hard copy even if other notices are digital.
What a combined notice covers
- 1Smoke detectorsOwner and tenant duties for installing and maintaining smoke alarms.
- 2Carbon monoxide detectorsWhere they go, who maintains them and the fee owners may charge. See our CO rules guide.
- 3Natural gas detectorsThe newest one, tied to the January 1, 2027 deadline.
- 4Suspected gas leak stepsLeave, call 911 from outside, call the gas company. Details in our gas leak notice guide.
Why owners like it
One sign instead of three or four means less wall space, a cleaner lobby and only one thing to update when the rules change. It also makes inspections easier, since everything about detectors and gas is in one place. The rest of the wall is covered in our checklist.
Ask us about a combined detector and gas leak notice for your building. See detector notices
The rules still apply
Combining notices doesn't relax the standards (see 28 RCNY Chapter 12). The posted notice should still be easy to read: HPD's detector and gas leak rules call for bold letters at least three sixteenths of an inch tall, high contrast, durable material like metal, plastic or a decal, and good lighting. Use HPD's sample language so nothing required gets left out.
Combined notice and digital screens
Since February 2, 2026, some notices can go on a digital screen. The combined detector notice can be shown digitally too, but there's one exception: the suspected gas leak notice must remain in hard copy. So if you put the combined notice on a screen, keep a physical gas leak sign on the wall as well. If the screen ever stops working, physical notices have to go up right away.
Is combining right for your building?
Small lobbies, vestibules, and buildings that want one clean detector sign.
Buildings without gas piping may not need the natural gas section. See Gas vs All Electric before ordering.
With the natural gas detector date coming, combining now saves a reorder later.
What this looks like in practice
Say a 4 story walk up has a narrow vestibule with room for maybe six signs. The owner needs the registration sign, super sign, inspection frame, fire safety notice, gas leak notice, smoke and CO notice, and soon the natural gas notice. Combining the detector and gas leak notices into one frees up two spots and keeps the wall from looking crowded.
Tips from our shop
- Put it near the inspection frame.
HPD's violation text places the CO notice near the inspection certificate. Our frame guide shows where that is.
- Include your gas company number.
The gas leak section needs your provider's emergency line.
- Recheck after rule changes.
Detector rules have changed several times. A combined sign is easy to replace in one go.
Official sources: HPD sample combined notice, 28 RCNY Chapter 12, HPD Required Signage.
Quick answers
Can one combined notice replace all the separate detector notices?
Yes, HPD allows one notice that combines the smoke, CO, natural gas and gas leak notices, using its sample wording.
Can the combined notice be on a digital screen?
Yes, except the gas leak part, which must stay in hard copy on the wall.
Do I still give tenants the gas leak notice with leases?
Yes. Posting a combined notice doesn't replace delivering the gas leak notice with every lease and lease renewal.
Not sure what your building needs?
Send us your address and number of apartments. We will tell you exactly which signs to order.
General information based on the NYC HPD Required Signage page as of November 2026. Not legal advice. HPD Signs NYC is not affiliated with the City of New York or HPD. Prices may change. Check nyc.gov/hpd for the latest rules.