Water Heater Repair
Track down the cause of cold showers, tank leaks, popping noises, pilot trouble or burned-out elements.
Homeowner tips
How to Flush a Water Heater in Westminster, CO
A flush drains sediment from the bottom of the tank. In moderately hard water it is a yearly chore that quiets the tank, improves heat transfer and slows corrosion.
By the Westminster Plumbing Co. team ·
Why flush
Minerals in the water settle on the bottom of the tank as sediment. A layer of it insulates the water from a gas burner or covers an electric element, so the heater works harder. Trapped water under sediment boils and makes a rumbling or popping sound.
Westminster's water report lists hardness near 7 to 8 grains per gallon. That is moderately hard, so sediment collects.
Before you start
Turn off power at the breaker for an electric heater. For a gas heater, set the control to pilot. Let the water cool for a bit, since the water inside is hot enough to scald.
Connect a garden hose to the drain valve at the bottom and run it to a floor drain or outdoors. Make sure the hose end is lower than the valve.
The flush
Turn off the cold inlet valve on top of the heater. Open a hot tap in the house so air can enter. Open the drain valve and let the tank empty. The water at first may be cloudy or gritty.
Open the cold supply briefly to stir the sediment, then close it and let the tank drain again. Repeat until the water runs clear.
Restart safely
Close the drain valve and remove the hose. Open the cold supply and leave the hot tap open until water runs steadily with no air. Only then turn the power or gas back on.
Never turn an electric heater on before the tank is full. The elements burn out when dry.
What you may find when you flush
The first minutes of flush water tell you a lot.
| What you see | What it means | Next step |
|---|---|---|
| Gritty or cloudy water | Normal sediment | Keep flushing until it clears |
| Rust-colored water | Corrosion inside the tank | Check the anode rod, plan for replacement |
| Water will not drain | A clogged drain valve | Replace the valve |
| A leak after the flush | A weak tank or valve | Tighten the valve or replace the tank |
Problems you might find
A drain valve that clogs with sediment or will not close is common on old tanks. Replace it with a brass or full-port valve. A leak at the valve after the flush needs tightening or replacement.
A heavy load of sediment, or a tank that has never been flushed, may be too far gone. A very old tank can leak after disturbing the sediment, so be ready to replace it.
When to call a plumber
Call if the drain valve is stuck, if the tank is old or if you are not comfortable with gas. A plumber can flush it, replace the anode rod and check the relief valve.
Westminster lists water heater installation and replacement among work that needs a permit. A flush does not need one, but a replacement does.
Tools and time
You need a garden hose, a bucket and a screwdriver or a wrench for the drain valve. Plan about an hour. If the tank has not been flushed in years, expect plenty of sediment, and be prepared for the drain valve to clog.
Run the hose to a floor drain or outdoors, away from plants. Water from the drain valve is hot enough to scald, so let the tank sit unheated for a few hours before you start.
What the flush can and cannot do
Flushing removes loose sediment and slows the buildup of scale. It does not reverse damage that has already happened. A tank with years of hardened deposits may still run noisily and heat slowly.
If the drain valve is plastic and seized, forcing it can break it. A plumber can swap it for a brass valve, which makes later flushes easier. That small upgrade is worth doing at the same visit.
Hard water and the bigger picture
The city reports hardness of about 7 to 8 grains per gallon, enough for scale to build steadily in any heater. A softener or a scale-reducing device cuts the buildup, and an annual flush keeps what remains in check.
Check the anode rod every few years as well. It is a sacrificial rod that protects the tank from rust, and replacing it can extend the life of the heater by years. A plumber can inspect it during a flush.
Signs your heater needs attention
Longer waits for hot water, a rumbling sound while it heats, and water that runs out sooner than it used to all point to heavy sediment. A flush often helps, but badly scaled tanks may need replacement.
Rusty hot water, drips from the temperature and pressure valve or moisture at the base mean the tank is aging. If the unit is more than a decade old, plan for replacement rather than repeated repairs.
Keep a record of the date of each flush and the condition of the water that came out. The log tells you whether the sediment is increasing and guides the next service interval.
Gas or electric: what changes
On an electric heater, switch the breaker off before you flush, or the elements can burn out when the tank drains below them. On a gas heater, set the control to pilot or off and let the burner cool before opening the drain.
Both types need the cold supply valve closed and a hot tap opened upstairs so the tank can drain smoothly. When you finish, refill the tank completely before you restore power or relight the burner.
Keeping a simple maintenance record
Tape a card near the heater and write the date of each flush, the anode rod check and any repairs. The record helps a technician understand the unit's history and helps you decide when replacement makes more sense than another repair.
Common questions
Answers about water heater flush
Many manufacturers suggest once a year. Hard water may call for more often.
Disturbing sediment can expose a weak spot and cause a leak. If the tank is very old, consider replacement instead.
Stirred sediment and rust particles. It should clear after a few minutes.
Yes, descaling is the equivalent. See the tankless service page.
Related services
Water Heater Installation & Replacement
Swap a dead tank for a new one and choose capacity, fuel type, venting and placement.
Tankless Water Heater Service
Flush scale, repair or put in an on-demand heater.
Keep reading
Water heater leaking from the bottom
Water at the base of the heater is either a loose fitting or a failed tank. A few checks tell you which, and what to shut off first.
Water hammer: why pipes bang
Banging pipes when a valve closes have a simple physical cause and a few common fixes.
Low water pressure: causes and fixes
Weak flow at one tap is a different problem from weak flow everywhere. Work through the usual causes before you call.
Heater noisy or not heating?
Call and say whether it is gas or electric. The dispatcher then matches you with a nearby contractor.