Water Heater Installation in Washington, IL

Which Type of Water Heater Fits Your House?

Most replacements stay with the fuel the house already has, because the pipes, venting and circuits are in place. These are the common types.

Switching fuel is a bigger job than a swap. It changes the gas line, vent or circuit, and sometimes the permit. Our tankless water heaters page covers that option on its own.

What Size Water Heater Do You Need?

Size to your busiest hour, not to the head count alone. The label on a storage tank lists a first-hour rating, which is how much hot water it can deliver in an hour starting from full. Compare that to your morning peak, when showers, the dishwasher and the washer may overlap.

Forty and fifty gallon tanks are common. Bigger households and homes with a soaking tub may need more. Water coming into a Central Illinois house in January is colder than in July, so a tank in winter has more work to do and its recovery rate counts. An undersized unit shows up as cold showers that arrive on the same morning every week.

Do You Need a Permit to Replace a Water Heater in Washington?

Permits vary by town and by the scope of the job, so ask the city before work starts. The City of Washington issues permits that last six months and can be renewed. Contractors register with the city, and rough-in plumbing must pass inspection before walls close. Whether a like-for-like tank swap needs a permit is the city's call. The city's inspection line is (309) 444-1122, Monday to Friday, 8:00 AM to 5:00 PM. Confirm with the city.

Outside Washington, call the village or city hall where the house stands. Separately, Illinois requires a license for anyone who installs plumbing. Ask for the number and check it in the IDPH license lookup.

How a Water Heater Replacement Goes, Step by Step

We follow the same order on every replacement.

1. Look at the existing setup. Fuel, size, venting, shutoffs, floor drain and clearances.
2. Quote the job. You get the unit, the parts and any code items in writing.
3. Shut off, drain and remove. Water, gas or power go off, the tank drains, and it comes loose from its lines and flue.
4. Set the new unit. It sits level, with a pan where a leak would damage floors.
5. Connect water, relief and venting. New shutoff valve and connectors, an expansion tank where needed, a discharge pipe to a safe point and a flue checked for draft.
6. Fill, light or power up, and test. Air is bled from the lines, gas joints get a leak check, and we confirm hot water.

What Goes in Besides the Tank?

The tank is only part of the job. The extras are what keep a leak or a vent problem from becoming damage, so check that each one appears in any quote you compare.

• Relief valve and discharge pipe. The pipe runs down to a point where hot water can drain safely.
• Expansion tank. Many homes with a check valve or pressure reducing valve at the meter need one.
• New shutoff valve. An old, stuck one is replaced, so you can shut the water in a leak.
• Drain pan. A pan under the heater limits damage where a floor is finished.
• Venting. Gas units need a flue that draws correctly, and a larger-diameter old chimney can be a problem for a smaller new unit.

In a house from the 1970s, the median build year for Washington, expect an older chimney connection and original shutoffs. Homes rebuilt after the 2013 tornado may have newer plumbing but the same fixes apply.

What Does Water Heater Installation Cost?

Today's Homeowner publishes an estimated range of $772 to $1,931 for water heater installation. It is an estimate, not government data and not our quote. Here is what moves the number:

• Type and size. A larger tank or a heat pump unit costs more than a standard tank.
• Fuel and venting changes. Moving from one fuel to another, or re-venting, adds labor and parts.
• Access. Stairs, tight closets and long runs take more time.
• Code items. Expansion tank, discharge piping, pan and new valves.
• Permit. If the city requires one, a fee applies.
• Disposal. Ask who hauls the old tank and what it costs.

Ameren Illinois lists a $50 rebate on a new ENERGY STAR gas storage or gas tankless water heater, one per household, bought by December 31 and claimed within 60 days, and a $1,150 instant discount on an ENERGY STAR heat pump water heater through participating contractors (as of 2026). Confirm both with Ameren before you buy. Federal 25C and 25D credits expired on December 31, 2025.

How Do You Care for the New Heater?

A few steps protect the investment.

• Write the install date on the tank and keep the paperwork.
• Plan an annual flush to clear sediment from the bottom of the tank.
• Have the anode rod checked on a schedule. Our water heater repair page explains why it matters.
• Test the relief valve discharge pipe visually. If it drips, call.
• Keep the area around the heater clear of storage.

Our water heater replacement cost guide compares tank and tankless costs in more detail.