Where the water is coming from tells you whether this is a $200 valve or a new tank. Here's how to tell the difference — and what to shut off first.
A puddle under the water heater is one of those things that looks like a catastrophe and sometimes isn't. A 50-gallon tank holds enough water to ruin drywall, flooring and anything stored nearby, so the first few minutes matter — but where the water is coming from decides whether you're looking at a small repair or a replacement.
First: stop the water and the heat
Before you diagnose anything, take the pressure off the system. These three steps take about a minute and prevent most of the expensive damage:
- Shut off the cold water supply — the valve on the pipe entering the top of the tank. Turn it clockwise until it stops.
- Kill the heat. On a gas heater, turn the dial on the control valve to 'Off' or 'Pilot'. On an electric heater, switch off its breaker — never drain an electric tank with the power on, or you will burn out the elements.
- If water is spreading, run a hose from the drain valve at the bottom of the tank to a floor drain or outside and open it. It's better to move the water on your terms than through the ceiling below.
If the water is hot and coming out fast
Get people away from it and shut off the main water valve to the house rather than hunting for the tank valve. Scalding is a bigger problem than water damage, and a failed tank can empty in minutes.
Now find where it's actually leaking
Dry everything, put down a few paper towels, and give it fifteen minutes. Water travels, so the puddle is rarely under the actual fault. Four places account for nearly every water heater leak we get called out to:
- The supply connections at the top. Flex lines and unions loosen over time. This is the cheapest outcome — usually a fitting, a gasket and half an hour.
- The temperature and pressure relief (T&P) valve, the one with a discharge pipe running down the side. If it's dripping, either the valve has failed or your system pressure is genuinely too high — and the second one needs solving, not capping.
- The drain valve at the bottom. Plastic drain valves get brittle and weep after being opened once. Replaceable.
- The tank itself. If water is coming from the bottom of the shell with no valve or fitting above it, the inner tank has corroded through. There is no repair for this — the tank is a sealed, glass-lined vessel, and once it's rusted through it's done.
Why tanks rust out sooner in Northern Colorado
Our water is hard — most of Loveland, Greeley and the surrounding towns run well above the point where scale starts forming. That scale settles on the bottom of the tank, insulates the burner from the water it's trying to heat, and drives the steel hotter than it should run. Meanwhile the sacrificial anode rod that's supposed to corrode instead of your tank gets used up quietly, usually within three to five years.
The practical upshot: a tank that might last twelve years on soft water often gives up around eight or nine here. Flushing the tank annually and replacing the anode rod before it's gone is genuinely the difference — it's a cheap service call that buys years.
Repair or replace?
Our rule of thumb, and we'll tell you this on the phone before we come out: if the leak is at a valve or a fitting, repair it. If the leak is the tank, replace it. And if the tank is over ten years old and needs a significant repair, put the money toward the replacement instead — you'll be buying one within a couple of years regardless.
It's also the natural moment to ask whether a tankless unit makes sense for your house. They cost more up front and need a bigger gas line in some homes, but they don't store 50 gallons of water waiting to leak, and they don't have a tank to rust out. We'll give you the honest comparison for your specific setup rather than a brochure answer.
When to stop reading and call someone
- You smell gas anywhere near the heater — leave the house and call the gas utility first, then us.
- The T&P valve is discharging steam or very hot water, which points at a control failure rather than a plumbing one.
- Water is reaching finished flooring, a furnace, or an electrical panel.
- You can't find the shutoff, or the shutoff won't turn.
We answer the phone around the clock for exactly this. Even if you just want a second opinion on whether it can wait until morning, call — we would rather talk you through a shutoff for free than meet you after the ceiling comes down.
