Chimney Liner Permits in Massachusetts: Which One Files

TL;DR

• A gas appliance liner is gas fitting work. It rides on the plumber's or gas fitter's permit.
• Only 24 of 8,000+ Massachusetts boiler and furnace records gained a liner record within a year.
• 248 CMR 5.12 sets when an old chimney can stay: no fan-assisted swap, seven-times flue area cap.
• Liner records that do file are building permits, mostly for stoves, and they peak September to December.

---

Yes, a chimney liner needs a permit in Massachusetts, but in most heating jobs you will never see it as its own record. When the liner serves a gas boiler, furnace or water heater, the state's plumbing and gas board treats it as part of the gas fitting work: it may be installed only under a licensed plumber or gas fitter who has secured a gas fitting permit for the job (Board policy, Venting of Flue Gases). A liner for a wood, pellet or coal stove goes with the building permit the stove itself requires.

That split explains a number in our file that surprises most chimney contractors. Of more than 8,000 Massachusetts records naming a boiler or furnace, only 24 were followed by a separate liner record at the same address within a year. The liner work happened, or it did not, inside the gas permit. If you wait for a liner permit to tell you a flue needs work, you are waiting for a record that will not come.

Which permit covers a chimney liner in Massachusetts?

It depends on what burns at the bottom of the chimney.

Appliance venting into the chimney	Permit the liner rides on	Who pulls it	Rule
Gas boiler, furnace or water heater	Gas fitting permit for the appliance	Licensed master or journeyman plumber or gas fitter	248 CMR 3.00 and the Board's venting policy
Wood, pellet or coal stove, or a wood insert	Building permit for the solid fuel appliance	Owner of the home, or a contractor with a fitting construction supervisor license	Massachusetts State Building Code (780 CMR)
Oil boiler or furnace	Oil burner permit from the local fire department	As the fire department requires	527 CMR 1.00
Chimney rebuilt or relined with no appliance change	Building permit in most towns (89% of liner records in our file)	Contractor with a masonry or broader construction supervisor license	780 CMR

The gas row is the one that matters most for volume. The Board's interpretation is blunt: the licensed plumber or gas fitter is responsible for every part of the gas fitting work on the permit, including venting the flue gases, and must be present for the final inspection. Chimney lining systems, metal and factory-built chimneys and B-vent for gas appliances may be installed by other qualified people only when that licensed fitter supervises them and holds the permit.

The solid fuel row comes from the state fire safety guidance, which says you need a building permit before installing fireplaces and wood, pellet or coal stoves, and that the local building inspector must inspect them before use (mass.gov fireplace and chimney safety). The same page says a solid fuel appliance must not share a flue with another solid fuel, fossil fuel or gas appliance, which is why a stove going into an old two-flue chimney often turns into a liner job.

When does a gas appliance need a new liner?

When the existing chimney fails the reuse test in the Massachusetts fuel gas code. Section 5.12 of 248 CMR 5.00 allows a tile-lined chimney, or an existing chimney that does not meet the model code, to serve a new or replacement gas appliance (including gas replacing oil) only when all three conditions hold:

1. The old appliance operated with non-positive vent pressure and did not create condensation in the chimney.
2. The job is not replacing an atmospheric appliance with a fan-assisted one. That swap rules the existing chimney out.
3. The chimney's interior area is no more than seven times the area of the smallest flue connected to it.

If any condition fails, the chimney cannot be used as it stands, and the fitter has to reline it or vent the appliance another way.

The third condition is where the orphaned water heater lives. A house with a gas boiler and a gas water heater sharing one masonry chimney replaces the boiler with a condensing unit that vents through the side wall. The boiler is gone from the chimney. The water heater, with a much smaller flue, now vents alone into a chimney sized for both, and the seven-times cap can fail on that one change. The fitter on the boiler permit is the person responsible for getting that right.

What does our permit data show about liner records?

Liner records are rare, and almost none follow a heating job. From January 2025 through September 2026 we hold 391 Massachusetts records whose description names a chimney or flue liner, a reline or a stainless liner, in 41 towns. Another 447 records mention a chimney without a liner (rebuilds, repairs, removals), for 838 in total.

How the 391 file:

• 349 building permits (89%), 28 sheet metal, 10 gas, 4 mechanical.
• 178 (46%) also name a wood, pellet or coal stove, an insert or a fireplace. 38 (10%) name oil. Only 20 name a boiler, furnace or water heater.
• 171 (44%) carry a contractor name.

Now set that against the heating side. Over the same 21 months we hold 8,131 records naming a boiler or furnace, and 1,032 of them name a condensing, high-efficiency, direct-vent, sidewall or power-vented unit. Matching on address within the same town, only 24 boiler or furnace records were followed by a liner record within 365 days, and just 2 of those were condensing or sidewall units. The median gap, where one existed, was 136 days.

That is the finding. The heating permit and the liner do not show up as two records. A chimney contractor who targets liner permits sees the solid fuel market and almost none of the gas market.

Where do Massachusetts liner records file?

They cluster where towns write full descriptions, and in stove country. These are the towns with 13 or more liner records in the 21 months:

Town	Liner records	Also name a stove, insert or fireplace	Boiler or furnace records
Falmouth	71	21	943
Holden	36	18	310
Pembroke	29	17	164
Melrose	22	10	410
Milton	19	11	275
Somerville	18	1	754
Reading	15	14	4
Easthampton	13	7	151

Two towns stand out. Somerville files 754 boiler and furnace records and only 18 liners, one of them tied to a stove: a dense city where any gas-side liner work sits inside gas permits. Reading's trade permits rarely describe the equipment, so its four heating records undercount the town's real volume, while its building permits name the stove on almost every liner.

Seasonality is sharp. In calendar 2025, 110 of the year's 208 liner records (53%) filed from September through December, against 15 from May through July. (August and September 2026 look higher still, but more towns began sending descriptions in those months, so they are not comparable with earlier ones.) Our wood stove permit article shows the same fall curve for the stoves themselves, and the August 2026 Massachusetts building permit report gives the statewide volume those liners sit inside.

How should a chimney contractor read these records?

A permit is a signal about the homeowner, not the contractor. A gas boiler permit tells you an owner just paid for new heat and has a licensed fitter on the job. It does not tell you whether the chimney passed the reuse test, and the owner often does not know either.

Read each record into one of three groups:

1. Gas boiler or furnace record naming a condensing, high-efficiency or sidewall unit. The appliance left the chimney. If anything else gas-fired still vents there, the flue may now be oversized. Highest priority, and the work belongs to the fitter: your offer is to the fitter as a lining subcontractor, or to the owner as a chimney inspection and cap, sweep and masonry repair on a chimney that may now serve one appliance or none.
2. Gas water heater replacement. Same reuse test. A swap to a fan-assisted or power-vent heater rules the old chimney out under condition 2, which usually means new venting rather than a liner.
3. Building permit for a stove, an insert or a liner. The liner may already be in scope, or the inspector will look for it before the first fire. Pre-use chimney inspection, sweep, cap and the annual cleaning account.

For the heating side of the same calendar, the fall boiler and furnace permit breakdown shows when replacements peak. Owners who are replacing a boiler should start from the furnace, boiler and AC replacement permit guide, and the removal leads after a heating swap cover the tank and old-boiler work that follows the same records.

Who can do the work, and when should you reach the owner?

The license decides who can sell what. On a gas appliance, the lining is done under the licensed plumber or gas fitter who holds the gas permit. A chimney company that does not hold that license is a subcontractor to the fitter on that job, and the best gas-side play is a standing arrangement with the fitters who file most in your towns.

On solid fuel, Massachusetts has a specialty construction supervisor license for solid fuel burning appliances. It covers installing the appliance and the inlet or exhaust elements the installation needs, but no structural work, not even sheathing (mass.gov construction supervisor licenses). Masonry work on the chimney itself sits under the specialty masonry license or a broader construction supervisor license.

Timing follows the appliance:

• Gas heating records. Weeks 1–3 after filing, while the fitter is still on the job and before the final inspection.
• Stove and insert records. Before the first fire. The inspector signs off before use, and in the fall cohort that is within a few weeks.

The HVAC contractor playbook covers how to split this work between your own crew and the fitters you sub for.

How permits.llc fits in

We aggregate 410,000+ Massachusetts permit records across 140+ cities and 13 counties, with the work description on each record, which is what lets you separate a condensing swap from a like-for-like boiler and a stove liner from a chimney rebuild. Start with the permit download page and pull gas and building permits for your towns, then set up daily permit alerts for your area so new heating and stove records reach you while the fitter and the inspector are still on site.