Yes, in most cases. Heating, cooling, and plumbing work can release refrigerant, carbon monoxide, sewage, or mold, and your general liability policy is written to exclude claims like those. Who this is for: owners of heating, cooling, plumbing, and mechanical contracting businesses who assume general liability covers everything.
The short version
- Insurers treat carbon monoxide, refrigerant, flue gases, and sewage as pollutants and deny those claims. A separate rule removes mold. Courts have not always agreed, but you would pay a lawyer to argue it.
- Your general liability policy has a pollution exclusion. Those claims are usually denied, including the legal defense.
- Contractors pollution liability is the policy that pays them. Many insurers sell it bundled with general liability for mechanical trades.
- Commercial customers, schools, and hospitals increasingly require it, usually at $1,000,000 to $2,000,000.
- Illustrative cost for a small heating, cooling, or plumbing shop is about $1,500 to $5,000 a year at a $1,000,000 limit.
What can go wrong on a heating, cooling, or plumbing job?
More than most owners expect. In your policy, a "pollutant" is any irritant or contaminant. It can be a solid, a liquid, a gas, or heat.
| What happened | Why the insurer calls it pollution | Who pays if the insurer denies |
|---|---|---|
| A flue is connected wrong and carbon monoxide fills a bedroom | Carbon monoxide is a gas contaminant. Courts in some states have disagreed. | You, unless you pay a lawyer |
| A refrigerant line leaks into an occupied office | Refrigerant is a chemical vapor | You |
| A furnace cracks and soot coats a house | Soot and smoke are named pollutants | You |
| A sewer line backs up into a finished basement | Insurers treat sewage as a contaminant and deny these. Courts in some states have disagreed. | You, unless you pay a lawyer |
| A slow leak behind a wall grows mold | A separate fungi and bacteria exclusion removes mold, and some insurers also argue the pollution exclusion | You |
Why won't my general liability policy pay?
Because nearly every general liability policy carries a pollution exclusion. It removes injury, damage, and cleanup claims caused by a release of pollutants. The standard form gives a few narrow things back. Many contractor policies add a total pollution exclusion, a separate page that removes even those.
| Where it is | What it means in plain English |
|---|---|
| Pollution exclusion in the standard policy (CG 00 01, exclusion f) | No payment for injury, damage, or cleanup from pollutants brought to a site where you are working. |
| Total pollution exclusion, a separate page on many contractor policies | Removes the narrow give-backs and applies after you leave the job. |
| Fungi or bacteria exclusion (CG 21 67), another separate page | No payment for mold or bacteria claims. This is the page that decides mold. |
The heating and cooling insurance guide and the plumbers insurance guide cover your other policies.
What does pollution insurance cover for a mechanical contractor?
The policy is called contractors pollution liability. It covers pollution claims from work you or your subs perform, and usually pays for:
- Bodily injury to customers, tenants, and anyone else who is not your employee.
- Property damage, including the cleanup and tear-out that follows sewage or mold.
- Cleanup costs ordered by a government agency.
- Legal defense, which alone can run past $30,000 in a carbon monoxide case. On most pollution policies defense comes out of the limit instead of on top of it the way general liability defense does. Ask which way your quote is written.
- Mold, the claim plumbers see most.
Many insurance companies sell mechanical trades one package with both coverages. Ask at your next renewal.
Do commercial contracts ask mechanical subs for it?
More every year. General contractors, school districts, hospitals, and property managers now ask. Typical asks:
- $1,000,000 to $2,000,000 of contractors pollution liability, sometimes $5,000,000 on hospital work.
- Your customer added to your policy, so they can use it if they are sued because of your work.
- No lower cap on mold claims, or a cap of at least $250,000. (A cap below the main limit is called a sublimit.)
- A policy that covers events that happen while it is active, even if the claim arrives later. Most trade pollution policies work that way.
If a contract asks for something you do not have, see where to get pollution insurance fast.
What does pollution insurance cost for a heating, cooling, or plumbing business?
These numbers are illustrative. Your revenue, state, service mix, and claims history set the real price.
| Business | Illustrative annual cost, $1,000,000 limit |
|---|---|
| Residential service shop, 1 to 4 employees | $1,500 to $3,000 |
| Residential and light commercial, 5 to 15 employees | $2,500 to $5,000 |
| Commercial mechanical, 15 to 30 employees | $4,000 to $7,500 |
See how to find cheaper pollution coverage.
How do I buy it and how long does it take?
Through a broker. Stand-alone pollution policies come from specialty insurance companies that do not sell online. Plan on 2 to 10 business days, a short application, and your claims history report.
What this looks like in real life
Illustrative example. It is typical of what we see and is not a promise of how any specific situation would be handled.
The setup: A plumbing contractor in New Jersey with nine employees replaces a sewer lateral at a two family house. He carries general liability and no pollution coverage.
What went wrong: A fitting fails two weeks later and raw sewage backs up into the finished basement apartment. The tenants move out. By the time the owner opens the walls, mold has spread across two rooms.
What it cost: The claim comes to about $64,000. His general liability insurer pays roughly $18,000 for plain water damage. It denies the mold under the fungi exclusion and the sewage under the pollution exclusion. Whether sewage counts as a pollutant has gone both ways in court, so his choice was to pay a lawyer or pay the bill. He pays about $46,000 himself.
The fix: For plumbers, sewage and mold are the two most likely large claims, and both fall outside general liability. Price pollution coverage before a contract makes you.
Frequently asked questions
Q: Does my heating, cooling, or plumbing business need pollution insurance?
In most cases yes. Insurers treat carbon monoxide, refrigerant, flue gases, and sewage as pollutants and deny those claims, and a separate page removes mold. Contractors pollution liability is the policy that pays them.
Q: Is carbon monoxide really a pollution claim and not a general liability claim?
Insurers usually treat it as pollution and deny it. Courts have not always agreed, so the outcome can depend on your state and your policy wording. The standard form's give-back for fumes from heating or cooling equipment applies at a building you own or rent, not at a customer's home.
Q: Does pollution insurance cover mold from a plumbing leak?
Usually yes, and that is the main reason plumbers buy it. Check whether the policy caps mold at a lower amount than the rest of the limit. Many contracts want that cap at $250,000 or higher, or none at all.
Q: Does it cover contamination that was in the building before I got there?
Usually not. These policies pay for what your work releases. Something that was already there is normally left out, though a few policies can add limited coverage for it.
Q: Do I still need it if my subs do the risky work?
Usually yes. The claim comes to you first, and your general liability excludes pollution from your subs' work as well as your own. Most pollution policies cover claims made against you because of a sub's work.
Q: Can my customer be added to my pollution policy?
Usually yes, and many commercial contracts ask for it. Tell your broker at the application stage so the wording is there from day one instead of added later.
How Morrow helps
Morrow is a licensed independent commercial insurance brokerage that works with contractors and trades every day. Pricing pollution coverage for heating, cooling, and plumbing contractors, alone or bundled with general liability, is a routine part of what we do for mechanical trades.
- Free contract review. Send us the contract or bid documents and we mark up the insurance section in plain English, whether or not you buy anything from us.
- Free, instant certificates. Clients issue their own certificates of insurance online in about a minute, any hour, any day, at no charge.
- Markets you cannot reach online. One application, shopped across many insurance companies for general liability, workers comp, auto, umbrella, and pollution coverage.
One more thing. This article is general information and is not legal advice or a statement of coverage. Your contract and your policy wording control in every case. Requirements vary by customer, by state, and by insurance company, so have a licensed advisor review your own contract and your own policy before relying on any of it.
Last updated: Reviewed by the Morrow commercial lines team. Last updated September 2026.