Why Is My Water Heater Leaking? A DFW Diagnostic Guide

The short answer: where the water is coming from tells you most of what you need to know. A drip at the cold-water inlet, the temperature & pressure (T&P) relief valve, or the drain valve is usually a repairable fitting. Water seeping from under the tank itself almost always means the inner tank has corroded through — and a corroded tank can’t be repaired, only replaced.

Use this guide to find the source before you call anyone. Ten minutes with a flashlight can save you a service visit — or tell you it’s time to compare replacement options.

Where is the water actually coming from?

Dry the tank and fittings with a towel, then check back in an hour. Water heaters leak from five places, in roughly this order of frequency:

• The drain valve (the spigot near the bottom). If it drips, the valve is loose or worn — an inexpensive repair.
• The T&P relief valve (the lever valve on the top or side with a discharge pipe). Occasional discharge can signal excess pressure in your system, not just a bad valve — this one deserves a professional look.
• The inlet and outlet connections on top. Loose flex lines or corroded dielectric nipples drip down the tank shell and mimic a tank leak.
• The gasket around the heating elements (electric models only).
• The tank itself. Rusty water pooling in or under the burner compartment, with no wet fitting above it, means the glass lining has failed and the steel is rusting through.

Is a leaking water heater dangerous?

A slow drip is a property problem, not a safety emergency — but it rarely stays slow. Tanks that have started to fail can open up quickly, and 40 to 50 gallons of hot water will find your slab, your flooring, and anything stored nearby. If the leak is heavy or the water is hot, shut it down now (next section) and treat it as urgent.

The exception is gas: if you ever smell gas near the water heater, leave the fittings alone and read our guide on what to do when you smell gas in your house before anything else.

How do I shut off a leaking water heater?

Two valves and a switch:

1. Water: turn the cold-water shutoff valve above the heater clockwise until it stops. If it’s stuck or broken, use your home’s main shutoff.
2. Gas models: turn the gas control dial to OFF, or close the gas valve on the supply line (handle perpendicular to the pipe).
3. Electric models: flip the water heater’s breaker in your panel. Never work around a leaking electric heater with the power on.

Why do water heaters fail early in North Texas?

Dallas–Fort Worth’s municipal water is hard — it carries enough dissolved calcium and magnesium that scale builds up on the bottom of a tank year after year. The sediment layer traps heat, stresses the steel, and eats the sacrificial anode rod ahead of schedule. In our service calls across Hurst, Bedford, Euless, and Fort Worth, hard-water sediment is the most common reason a tank fails before its warranty says it should. We cover the mechanics in what DFW’s hard water does to your plumbing.

Annual flushing helps — it’s one of the items included in the Gator Family Membership’s yearly plumbing evaluation.

Repair or replace: how do I decide?

Our rule of thumb from the trucks: a fitting leak on a heater under 8 years old is worth repairing. A tank leak, or any leak on a heater past 10 years, is replacement territory — you’d be putting new parts on a vessel that’s already failing. Tioga Plumbing installs tank water heaters across DFW for $1,850–$2,800 (40–50 gallon) with a written flat-rate price before work starts, and every installation is permitted; most DFW cities, including Hurst and Fort Worth, require a plumbing permit for water heater replacement, and Tioga files it for you.

Frequently asked questions

How long do water heaters last in DFW?

Plan on 8–12 years for a tank unit in DFW — hard water pushes most tanks toward the early end of that range unless they’re flushed regularly and the anode rod is checked.

Can I keep using hot water if the heater is leaking?

If the leak is a small drip from a fitting, yes, short-term. If water is coming from the tank body, shut it off — a failing tank can open up without warning.

Does homeowner’s insurance cover a leaking water heater?

Policies typically cover sudden water damage to your home but not the worn-out heater itself. Document the leak with photos before cleanup either way.

What does a diagnostic visit cost?

Tioga’s service call is $89, and it’s waived when you book the recommended repair. You get a written flat-rate quote before any work starts.

Do I need a permit to replace a water heater in Texas?

In most DFW jurisdictions, yes — water heater replacement requires a plumbing permit and inspection. Tioga pulls the permit in your city (Hurst, Fort Worth, Bedford, Grapevine, and beyond) as part of the job.

Is a leaking T&P valve an emergency?

It’s urgent. The T&P valve is a safety device — if it’s discharging, either the valve has failed or your system pressure is too high. Have it evaluated promptly rather than capping or plugging it, which is dangerous.

Next step: compare your replacement options

If your tank is the problem, the real decision is what goes in its place — a like-for-like tank or a tankless unit. The math is different in DFW than the national averages suggest.

Compare tank vs. tankless water heater costs in DFW →

Related reading

• Water heater repair & installation in DFW — our service page
• 7 slab leak warning signs in North Texas homes
• What DFW’s hard water does to your plumbing
• Not sure what’s leaking? Try the 60-second visual diagnostic