What it costs to run
The Energy Saver program at energy.gov describes water heating as the second largest expense in the average American home, accounting for 14% to 18% of the utility bill, or roughly $400 to $600 a year.
How long it lasts
Energy Saver gives typical service lives by type:
- Storage (conventional tank): 10 to 15 years
- Tankless / demand: about 20 years
- Heat pump: 10 to 15 years
- Solar: about 20 years
- Tankless coil and indirect: about 10 years
If you do not know the age of your tank, the manufacturer's label usually encodes it in the serial number. A storage tank past twelve years is on borrowed time, and the useful question stops being whether to replace it and becomes whether you replace it on your schedule or its own.
What a flush costs
Sediment collects at the bottom of a storage tank and makes the burner work harder to heat the water above it. HomeAdvisor puts the cost of flushing a water heater at $110 to $200, averaging $160, with tank-style units at the lower end, about $75 to $150, and tankless units at $150 to $250. The same guide notes some jobs run as low as $75 or as high as $250 in more complicated situations.
Signs it is near the end
Rust-colored hot water, a rumbling or popping noise from the tank while it heats, water pooling around the base, or hot water that runs out noticeably faster than it used to are all worth a look. Any standing water around a tank should be treated as urgent: a tank that is weeping at a seam can go from a drip to a full failure without much warning.
For what a plumber visit runs in this area, askdoss reports Milwaukee metro service call fees of $75 to $125 and standard hourly rates of $95 to $150, with water heater repair generally $200 to $600 and tank replacement $1,200 to $2,800.
Sources
Every figure above comes from one of these. Where they disagree, the post says so rather than averaging them into a single number.