How Often Should You Flush a Water Heater in Westminster, CO?

Most water heaters should be flushed once a year. In Westminster, CO — where water hardness levels are elevated — flushing every 6 to 12 months is a better target. Sediment from minerals like calcium and magnesium collects at the bottom of your tank. Over time, this makes your heater work harder, raises your energy bill, and shortens the unit's lifespan. A flush takes about 30–60 minutes and can add years to your water heater's life.

Already seeing signs of trouble?  Schedule water heater repair in Westminster

Why Water Heater Maintenance Matters More in Westminster, CO

Westminster sits in a hard water zone. According to Denver Water's annual water quality report, the Denver metro area consistently registers elevated hardness levels — often in the range of 8 to 15 grains per gallon depending on the source. That's considered hard to very hard water.

When hard water heats up, calcium and magnesium minerals separate from the water and sink to the bottom of your tank. That layer of sediment acts like insulation between the burner and the water. Your heater has to work harder and run longer to reach temperature. The U.S. Department of Energy notes that sediment buildup can measurably reduce water heater efficiency — meaning higher bills for the same amount of hot water.

Westminster homeowners feel this more than people in softer-water cities because the mineral load coming into the tank is higher from the start. The same issue affects tankless units, which develop scale buildup in the heat exchanger if not descaled regularly.



In Westminster homes we service, we often pull sediment layers that homeowners didn't know were there — even in tanks that are only 4–5 years old. That's a direct result of this area's mineral content.

Water Hardness vs. Recommended Flush Frequency

Signs Your Water Heater Needs to Be Flushed (Or Already Has a Problem)

Some symptoms show up gradually. Others are hard to miss. Here's what to look for:

Rumbling or popping sounds — Sediment trapped under the heating element cracks and pops as it heats up. This is one of the most common signs of buildup.

Slow or inconsistent hot water — If hot water takes longer than it used to, or the temperature fluctuates, sediment may be affecting heating performance.

Rusty or discolored water from the hot tap — Rust-colored water from the hot side only usually points to corrosion inside the tank.

Rising energy bills with no change in usage — The Department of Energy links sediment buildup directly to reduced efficiency and higher operating costs.

Moisture or pooling at the base of the tank — Even a small amount of standing water near the unit warrants a closer look.



Quick visual check: Look at the area around the pressure relief valve and the base of the tank. Any signs of moisture, mineral staining, or rust are worth noting before you call.

How to Flush a Water Heater Step by Step

What you'll need:

• Garden hose
• Flathead screwdriver
• Bucket (optional, for testing the drain valve)

Steps:

1. Turn off the power or gas. Switch your electric heater to "off" at the breaker. For gas units, set the thermostat to "pilot."
2. Shut off the cold water supply. The cold water inlet valve is typically at the top of the tank.
3. Let the water cool. Wait at least an hour. Water inside the tank can be hot enough to cause serious burns.
4. Connect a garden hose to the drain valve. The drain valve is near the bottom of the tank. Run the hose to a floor drain or outside.
5. Open a hot water faucet somewhere in the house. This prevents a vacuum from forming and lets the tank drain properly.
6. Open the drain valve. Water will begin flowing out. It may look brown or discolored at first — that's the sediment.
7. Flush until the water runs clear. Briefly turn the cold water supply back on to stir up remaining sediment, then drain again.
8. Close the drain valve, remove the hose, and refill the tank. Keep the hot water faucet open until water flows steadily — this means air has cleared the lines.
9. Restore power or gas once the tank is full.

Safety notes: Never drain a tank that hasn't cooled. Be careful around the pressure relief valve — it releases hot water and steam if triggered. If rust-colored water doesn't clear after several minutes of flushing, stop and call a plumber.

One thing we see often — homeowners open the drain valve and it won't fully close again afterward. Older valves corrode and fail to seat properly once disturbed. If that happens, stop and call us rather than leaving it dripping.

Not comfortable doing this yourself?   Call our Westminster plumbers

How Often Should You Flush Your Water Heater in Colorado?

The standard industry recommendation from manufacturers like Rheem, Bradford White, and A.O. Smith is once per year. In Westminster and across Colorado's Front Range, that baseline doesn't account for local water hardness — so we recommend adjusting based on your household situation.

Recommended Schedule by Household Profile

If you've never flushed your water heater — do it now, regardless of age. You may find the tank is in worse shape than you expected, and that's useful to know sooner rather than later.



For tankless water heaters, the process is different. Tankless units need annual descaling — a vinegar or descaler solution is circulated through the heat exchanger. The flushing steps above apply to traditional storage tanks only.

When Water Heater Maintenance Becomes a Repair Call

Flushing handles sediment. It doesn't fix everything. Here's where the line is.

What's maintenance:

• Flushing sediment from a working tank
• Checking the anode rod (and replacing it if worn)
• Testing the pressure relief valve
• Adjusting the thermostat setting

What's a repair:



• Leaking tank or drain valve that won't close
• Corroded or failed anode rod (accelerates tank corrosion if left alone)
• Pilot light that won't stay lit on a gas unit
• No hot water despite power and gas being on
• Active rust in the discharge water after flushing

DIY vs. Call a Pro

According to Angi's cost data, the average water heater repair runs significantly less than a full replacement. Catching a failing anode rod or a corroded fitting early almost always costs less than waiting until the tank fails.

Our team serves Westminster, Thornton, Broomfield, Arvada, and surrounding communities across Adams County and Jefferson County. A professional water heater inspection covers the tank, connections, anode rod, pressure relief valve, and gas or electrical components — so you know exactly what you're working with.

Let's take a look before it becomes a bigger problem.  

Evidence Pack