Most homeowners find out their water is hard when a plumber tells them, standing next to a heater that's eight years old and finished. By then the interesting part has already happened.
Here's what's going on inside that tank, why it happens faster around here than in a lot of the country, and what's genuinely worth doing about it.
What "hard" actually means
Hardness is dissolved mineral content — mostly calcium and magnesium — measured in grains per gallon. Anything above about 7 gpg is considered hard. Water in the Tomball area commonly runs 15 to 25 gpg, and much of the supply across north Harris and Montgomery County is firmly in the hard range.
That mineral doesn't stay dissolved when you heat it. Heat drives it out of solution, and it precipitates onto the nearest surface — which, in your house, is the inside of your water heater.
What it does to a tank heater
Sediment settles on the bottom of the tank. On a gas unit, that's directly over the burner.
Three things follow. The sediment layer insulates the water from the flame, so the burner has to run longer to deliver the same hot shower — you pay for that in gas. It creates localised hot spots on the steel, which stresses the glass lining that's the only thing standing between the water and bare metal. And once there's a decent bed of it, water trapped underneath flashes to steam and forces its way up through it, which is the rumbling and popping you hear from an older heater. That noise isn't cosmetic. It's a progress report.
Then there's the anode rod. Every tank heater has one — a sacrificial rod of magnesium or aluminium whose entire job is to corrode so the tank doesn't. Hard water consumes it faster. When it's gone, the tank starts corroding instead, and the clock to failure runs quickly from there.
That's the mechanism behind a heater that "should have lasted twelve years" giving up at eight.
What it does to a tankless unit
Tankless heaters don't have a tank for sediment to settle in, which sounds like an advantage and is actually the problem. The mineral deposits inside the heat exchanger instead — a narrow passage where the water is at its hottest, which is exactly where precipitation is worst.
Scale there restricts flow, forces the unit to fire harder for the same output, and eventually produces error codes or an inability to hold temperature at full flow. A tankless heater on hard water that's never been flushed is a unit running with a handicap it can't tell you about until it faults.
What actually helps
Check the anode rod around year five. This is the highest-value, lowest-cost thing on the list, and almost nobody does it. Replacing a consumed rod is inexpensive and can add real years to a tank. Once you've let it go entirely, you're not extending the heater's life — you're counting down.
Flush a tankless unit annually. On our water this is maintenance, not repair. It's a straightforward service call when the unit has isolation valves fitted, and an awkward one when it doesn't — which is why we install them as standard on every tankless we put in, whether or not anyone asks.
Draining a few gallons off a tank heater periodically helps somewhat with loose sediment, though it does less than the internet suggests once a hard layer has formed.
Consider treating the water. We're plumbers, not water treatment salespeople, and we'll tell you when it isn't worth it. But in Tomball and the harder parts of Spring, the arithmetic tends to favour it: whatever softening costs, it's usually less than replacing heaters, cartridges, angle stops and fixtures on the schedule hard water sets. If you're on a private well out toward Cut and Shoot, add iron and sediment to the case.
The signs your heater is further along than you think
- Rumbling or popping during recovery
- Hot water running out faster than it used to
- Rusty or discoloured hot water, especially after the house has sat unused
- Gas usage creeping up without a change in habits
- Any dampness around the base of the tank
The last one isn't a warning — it's a result. Once water is coming from the tank itself rather than a fitting, the lining has failed and no repair brings it back.
Worth a look before it decides for you
If your heater is past eight years and sits in an attic — common across Porter, Spring and the older Woodlands villages — replacing it on your schedule costs a great deal less than replacing it on its own, through a ceiling.
We'll look at it and tell you honestly whether it has years left or months, with no service fee either way. Call (832) 885-9820.