Short answer
Not for an in-kind swap. Chicago's Department of Buildings says repairing or replacing a hot water heater in-kind needs no building permit in a residential building up to 4 stories. The work must still meet code and be done by a licensed plumber, or by an owner-occupant under a narrow state exception.
Key facts
- The Chicago Department of Buildings lists repairing or replacing (in-kind) a hot water heater in a residential building up to 4 stories above grade as work that does not require a building permit.[1]
- Work done without a permit in Chicago must still comply with all Chicago Construction Codes, per the Department of Buildings.[1]
- Under 225 ILCS 320/3, an owner-occupant of a single-family home may do their own plumbing, to code and subject to inspection, but may not employ anyone other than a licensed plumber to help.[3]
What does Chicago's permit rule actually say?
The City of Chicago's Department of Buildings (DOB) keeps a list of work that does not need a building permit. Under plumbing work, it lists "repairing or replacing (in-kind) a hot water heater" in a residential building up to 4 stories above grade[1]. The same page adds that work done without a permit must still comply with all Chicago Construction Codes[1].
So the common claim that "Chicago always requires a permit for a water heater" is wrong for a like-for-like swap. It is right for many other jobs. Work outside the no-permit list needs a building permit. If you are not sure which side a job falls on, the DOB assistance counter on the 9th floor of City Hall answers that question[1].
When does a water heater job stop being in-kind?
In-kind means the new unit matches the old one in type, size and shape. These changes take you outside the no-permit rule:
| Change | In-kind? | What to do |
|---|---|---|
| Same type and size, same spot (40 gallon gas tank for 40 gallon gas tank) | Yes | No building permit in a residential building up to 4 stories[1]; still must meet code |
| Tank to tankless | No | Check with DOB; expect a permit |
| Larger tank, or gas to electric or heat pump | No | Check with DOB; expect a permit |
| Moving the heater to another room | No | Check with DOB; expect a permit |
| Building taller than 4 stories | Not covered by the rule | Ask DOB before work starts |
A tankless or heat pump swap often adds gas line, venting or electrical work too. Those changes are why the city treats them differently.
Who is allowed to do the work in Chicago?
Two layers apply: the city's rule on who may do plumbing work, and the state license law.
The city. DOB says plumbing work in Chicago is done by a Chicago-licensed and bonded plumbing contractor. The exception is that an owner, occupant or lessee may do the work personally, to code and subject to inspection, but may not hire anyone who is unlicensed[2].
The state. The Illinois Plumbing License Law says plumbing is to be performed by licensed plumbers and licensed apprentices working under supervision[3]. Section 3(2) lets the owner-occupant or lessee-occupant of a single-family home do their own plumbing on that home, with conditions[3]:
- The work must meet the Illinois State Plumbing Code and is subject to inspection.
- The owner may not employ anyone other than a licensed plumber to help.
- "Occupant" means living there as your sole residence and intending to stay at least 6 months after the work.
This is narrower than the "anyone can install their own" advice online. It does not cover a two-flat or three-flat you own but rent out, a rental you do not live in, or a paid friend who is not licensed. The Illinois Department of Public Health (IDPH) licenses plumbers statewide and runs a license verification tool[4]. See how to check a Chicago plumber's license.
What about the gas side?
Peoples Gas delivers natural gas to more than 898,000 customers in the city of Chicago[5]. Disconnecting and reconnecting a gas water heater, its venting, and its relief valve piping is licensed work. Do not attempt it yourself unless you fit the owner-occupant exception and know the code, and even then a licensed plumber is the safer choice.
If you smell gas near the heater, leave the house now. Do not use light switches or phones inside. Call Peoples Gas or 911 from outside. See gas smell near a water heater.
Does a permit change the price?
It can. We have not found a published flat fee for a Chicago water heater permit; the fee depends on DOB fee tables. Ask any contractor quoting a non-in-kind job to list the permit fee and inspection as separate lines. For typical installed prices, see water heater replacement cost.
When to call a pro
- You are changing the type, size or location of the heater: a licensed plumber can tell you whether DOB needs a permit and pull it.
- You rent the home, own it as a rental, or would need any helper: Illinois law points you to a licensed plumber.
- You smell gas, see scorch marks at the burner, or the relief valve is discharging: leave gas work to a licensed plumber or Peoples Gas.
- Your building is over 4 stories: ask DOB and a licensed plumbing contractor before work starts.
More questions
Is switching from a tank to a tankless water heater in Chicago still in-kind?
No. In-kind means the same type, size and shape. A tank to tankless change, a bigger unit, or a move to a new spot is outside the no-permit rule, so check with the Department of Buildings before the work starts.
Does a condo or a large apartment building follow the same rule?
The no-permit rule the city publishes covers residential buildings up to 4 stories above grade. For a taller building, ask the Department of Buildings what the job needs before you hire.
Can my landlord's handyman replace the water heater in my Chicago apartment?
Not under the owner-occupant exception. It covers an owner or lessee doing work on the single-family home they live in, and it bars employing anyone other than a licensed plumber. A rental unit swap belongs with a licensed plumbing contractor.
Sources
- What types of work do not require a building permit? Plumbing work, City of Chicago, Department of Buildings. Accessed 2026-10-06.
- Who can do plumbing work? (plumbing license FAQ), City of Chicago, Department of Buildings. Accessed 2026-10-06.
- 225 ILCS 320/3, Illinois Plumbing License Law, Illinois General Assembly. Accessed 2026-10-06.
- Plumbing program, Illinois Department of Public Health. Accessed 2026-10-14.
- About Peoples Gas, Peoples Gas. Accessed 2026-10-06.
Water Heater Facts is an information and referral service run by Strive LeadGen LLC. We may be paid by contractors when we connect a homeowner with one; that never changes what we publish. Found an error? Tell us. We review safety and legal reports within 2 business days and all others within 7 days.