How hard is a water heater installation?
Swapping a water heater is moderately hard for a trained plumber and risky for most homeowners. The water connections are the easy part. The hard parts are gas piping, venting exhaust safely, setting the relief valve and drain correctly and meeting local rules. Mistakes in those areas can cause carbon monoxide, gas leaks or scalding.
Illinois requires a license for anyone who installs, alters or repairs plumbing. The City of Darien requires permits whenever plumbing is changed, and does not list water heaters on its permit page, so ask Community Development at 1702 Plainfield Rd what applies.
Below we break the job into steps so you can see where the risk sits. A correct install follows manufacturer guidelines for clearances and venting, along with the standards in the Illinois Plumbing Code (Title 77, Part 890 of the Illinois Administrative Code).
Each part of the job, rated by difficulty and risk
The difficulty depends on the unit. Electric heaters have fewer risks than gas.
| Task | Difficulty | What can go wrong |
|---|---|---|
| Draining and removing the old tank | Moderate, heavy lifting | Scalding, flooding, back injury |
| Water connections and shutoff valves | Easy to moderate | Leaks at fittings, wrong connectors |
| Gas line and shutoff | High | Gas leak, fire, explosion |
| Venting and draft | High | Carbon monoxide entering the house |
| Temperature and pressure relief valve and drain line | Moderate | Scalding discharge, no safety relief |
| Electric wiring for an electric unit | Moderate to high | Shock, fire, wrong breaker size |
| Expansion tank where needed | Moderate | Pressure spikes, relief valve dripping |
Never work on gas piping yourself. If you smell gas, leave the house and call 911 or the gas utility.
The gas and venting problem
A gas water heater burns fuel and must send exhaust outside. The vent needs the right size, slope and clearances, and the heater needs enough air to burn cleanly. A poor vent can let carbon monoxide spill into the house, and you cannot see or smell it.
Gas connections must be leak tested with the proper method. Never use a flame to check. If you smell gas at any time, leave, call 911 and do not use light switches.
This is why we do not recommend do-it-yourself gas heater work. Our water heater installation page lists the connections and checks a plumber completes.
What a professional install looks like
- 1
Check the old setup
The plumber reads the old unit, checks the vent, gas line, shutoffs and available space.
- 2
Drain and remove
Power or gas is shut off, the tank is drained and the old unit is disconnected and carried out.
- 3
Set and connect
The new unit is set, water lines and shutoffs are connected, and the relief valve and drain are piped.
- 4
Connect fuel and vent
Gas or electric connections are made, the vent is sized and sealed, and joints are leak tested.
- 5
Fill, light and test
The tank is filled before power is on, the burner is lit or the elements are energized and combustion and temperature are checked.
Darien basements, fire district and the first minutes after a gas smell
Most Darien water heaters sit in basements or utility closets in houses built from the 1960s onward. Those spaces are tight, and older vents and gas shutoffs may have aged. Check the vent connection and the date on the existing unit before you plan a replacement.
If you ever smell gas, leave the house and call 911. Darien is served by the Darien-Woodridge Fire Protection District at 7550 Lyman Ave, and Tri-State Fire Protection District covers part of the city east of Cass Ave and north of I-55. Calling 911 reaches the right one.
Darien buys Lake Michigan water from the City of Chicago. The City does not publish a hardness figure, so test your tap or call (630) 353-8105. Mineral buildup affects tank life and is a fair question to raise with your installer.
When doing it yourself is not a good idea
Some jobs look easy until the details show up.
- Any gas heaterGas connections and venting need training and testing equipment.
- Switching fuel typeMoving from gas to electric changes wiring, breakers and venting.
- A new locationMoving the heater means new pipe, new vent paths and new permits.
- Tankless conversionsDifferent gas supply, venting and water requirements apply. See our tankless water heater page.
If the tank has already failed and is leaking, treat it as urgent. Our water heater replacement page covers same-day options when available.
What affects the cost of a water heater installation
The unit is one part of the price. The setup around it changes the rest. You hear a clear price before work starts.
Want a price for your house? Call (630) 822-9290 and tell us the fuel and tank size.
Replacing a water heater?
Tell dispatch what you have now. We can say what the install involves before anyone drives out.
What to ask before you hire an installer
Ask whether the installer holds an Illinois plumbing license. Illinois offers a public license verification tool. Ask what will be done with the old vent, who handles the permit question and what the work includes, such as new shutoffs and a relief valve line.
If the unit is in Willowbrook or the nearby villages, our Willowbrook service page explains how the same dispatch line covers it.
Water heater installation questions from Darien homeowners
Yes. Our dispatch line is open 24/7 at (630) 822-9290. Planned installs are scheduled by appointment, and same-day appointments are offered when available.
Illinois requires a license for anyone who installs, alters or repairs plumbing. Rules for a homeowner's own residence can differ, so check with the state and the City of Darien.
The City lists permits for plumbing changes but does not specifically list water heaters. Ask Community Development at 1702 Plainfield Rd.
A straightforward swap often takes a few hours, then the tank needs time to heat. Vent, gas or code updates add time. The plumber gives you a better estimate on site.
Shut off the cold water to the heater and the gas or power, then call. A leaking tank cannot be repaired and usually needs replacement.
Yes. We serve Willowbrook and Westmont from the same dispatch line, along with Downers Grove and Woodridge.