Rental Property CO Alarm in Lexington, MA: Leave, Call 911

A tenant calls: the alarm in the basement won't stop. They may not know whether it's a smoke alarm or a carbon monoxide alarm. Before any question about the boiler, tell them this:

Take everyone outside now, call 911 from outside, and don't go back in until responders say the building is safe.

That is the whole first response to a carbon monoxide alarm, a smoke or fire alarm, or an alarm nobody can identify. It's a life-safety call before it's a boiler, gas or maintenance call.

If you're the landlord and you're not there

Give that instruction first and gather details later. If you can't reach the tenant again or can't confirm that 911 was called, call 911 yourself. Give the exact Lexington address, the unit number, how many people you believe are inside and what the tenant reported. Don't make your drive to the property a condition for emergency action.

Never tell a tenant to:

• stay put, or wait for you or a plumber;
• go down to the basement or look at the boiler;
• silence, reset or unplug the alarm;
• have a neighbor, superintendent or handyman check it first.

If the alarm stops before everyone is out, they should still leave and call 911 from outside. A quiet alarm doesn't mean the air is safe or that the device was faulty.

If anyone smells gas

The response is the same: everyone leaves and calls 911 from outside. Don't use a phone inside, switch lights or appliances on or off, touch a thermostat or gas valve, or go looking for the source. Stay out until the fire department or gas utility says it's safe. Any plumbing or boiler work comes after that clearance.

Why nobody should try to identify the alarm first

Smoke and fire, carbon monoxide and a fuel-gas leak are different hazards, and a description over the phone ("the basement alarm keeps going off") can't tell them apart. Carbon monoxide has no smell; it can come from incomplete combustion or a venting problem with fuel-burning equipment. Natural gas is odorized, so a leak may have a recognizable smell. An alarm can also sound because of a wiring problem or a device at the end of its life. Responders have the equipment to sort that out safely. The tenant's only job is to get out.

After responders clear the building

Once the fire department, and the gas utility if it was involved, has cleared the property, find out:

• what responders found, and whether they shared any readings;
• whether the gas utility was involved and what equipment was shut off or tagged;
• whether re-entry was authorized for the whole building or only part of it;
• what they require before equipment is used again.

Those answers are far more useful to the next trade than a guess about a beep pattern.

The findings decide who comes next. A boiler, venting or hydronic concern fits a licensed plumber's boiler repair work. Customer-owned gas piping and appliance connections fit gas line repair once the utility has done its part; the utility stays responsible for its own main, service line and meter. An alarm device or building wiring issue goes to an alarm contractor or electrician, and a chimney question goes to a chimney professional.

No one should restore gas service or relight shut-off equipment outside the sequence set by the utility and any required permits and inspections. A next-day appointment is fine when responders have handled the event and said follow-up can wait. What's never fine is booking a contractor as the first response while people are still inside.

Keep the record factual

Write down who responded, what was shut off, what they told you, whether re-entry was authorized and what they required next. Don't rewrite the event as "the boiler leaked gas and caused CO" unless qualified testing established both. Keep tenants updated on which trade is coming and on any restrictions responders set, without promising a repair time nobody has confirmed.

Before the next alarm

When nothing is sounding, a rental benefits from routine boiler maintenance and a written record: make and model, past work, permits, service dates, tenant contact instructions and who can approve repairs. Put the emergency rule at the top of that sheet, where tenants will see it first: if an alarm sounds or anyone smells gas, leave and call 911 from outside before calling anyone else. Maintenance can find worn parts or venting concerns, but it can't guarantee an alarm will never sound. For which alarms your building needs and where, ask your alarm provider or the local fire department.

What we do after clearance

Jeneral Plumbing is based in Westford, MA, and owner-operated by a Licensed Master Plumber (MA #9628831-PL-M) with 20+ years in the trade, including seven with a gas utility. After a building has been cleared, we assess and repair boilers, hydronic systems and accessible customer-owned gas piping in Lexington and other Middlesex County towns. We don't survey whole buildings for CO, repair alarm systems or building wiring, approve chimneys, or decide when a building is safe to enter. We confirm the address, the work and availability before booking.

A scheduled regular-hours visit carries an $80 dispatch fee — the cost of the visit, waived when you hire us for the work. If responders have cleared the building and you need a boiler or gas-piping visit after hours, we take emergency calls 24/7, with arrival confirmed by phone. Off-hours, Sunday and holiday dispatch carries a separate $599 emergency callout fee; it is non-refundable and non-negotiable, collected prior to dispatch, covers the dispatch only and is never applied to repair work. Approved repairs are priced at a flat rate before work begins.

Call (978) 392-7789 after the building has been cleared, and tell us what responders found and what they asked you to do next.