Rusty or brown hot water: what it means and what to do

Test: hot only, or hot and cold?

Run the cold tap for a minute and look at it in a white cup. Then do the same with the hot. That tells you where to look.

Hot only: the water heater

Rheem says brown or reddish hot water often points to corrosion inside the tank or a deteriorating anode rod. Some discoloration can be fixed with maintenance or a new anode. Persistent rust usually means the heater is near the end of its life.

• Have the anode rod checked. If it's gone, the tank is exposed.
• A flush can clear loose sediment.
• If the tank is 10 or more years old and the water stays rusty, plan a replacement before it leaks.

Hot and cold: usually the water main

When a utility flushes its mains or opens hydrants, minerals settled in the pipes get stirred up. Denver Water says this can cause discoloration but is harmless and the water is safe to drink. Its advice:

• Avoid using hot water, including laundry and the dishwasher, so the discolored water isn't drawn into your water heater.
• Run cold water from a laundry sink, bathtub or, preferably, an outside spigot until it runs clear.
• If discolored water did get into the heater, you may want to flush the tank from the drain valve.
• Rewash discolored laundry before drying it.

Wheat Ridge, Colorado is one of the towns served by Denver Water (see our Wheat Ridge page).

Other causes

In older homes, galvanized steel pipes can rust from the inside and color the water, hot or cold. Homes on private wells can also see brown water from minerals in the groundwater. A water test or a plumber's inspection tells you which.

When to call

• Hot water stays rusty after a flush
• You also see water around the base of the tank
• The heater is 10 or more years old

Rust plus a leak means the tank is failing. Don't wait for it to let go (see signs a water heater is going bad).

Local pages mentioned

• Wheat Ridge, CO