Sometimes, small spurts after a heating cycle are normal, but steady dripping or puddles spell trouble.
A thimbleful of hot water hissing out of the temperature‑and‑pressure (T&P) relief valve may look scary, yet it’s often just the heater doing its job. The valve pops open if the tank reaches 150 psi or 210 °F to stop a dangerous pressure build‑up.
What isn’t normal is a constant drip, a wet floor, or water seeping from fittings on the tank body. Below you’ll learn how to tell the difference, fix the common causes, and know when it’s safer to call our team.
Why Water Comes Out of a “Closed” Tank
Most U.S. homes now have a back‑flow preventer or meter check valve that traps expanding hot water inside the plumbing loop. If no expansion tank is installed to absorb that extra volume, the pressure spikes and the T&P valve vents. Current plumbing codes list a thermal‑expansion tank as mandatory in such closed systems.
Another culprit is household water pressure. Experts put healthy pressure between 45 and 60 psi; 80 psi or more is too high and often the root cause of endless weeping at the relief drain.
Main Reasons Your Hot Water Heater Releases Water
| Cause | Why It Happens | Quick DIY Fix | Typical Cost* |
| T&P valve doing its job | Tank passes 150 psi/210 °F | Monitor; valve should stop within seconds | Free |
| No expansion tank or failed bladder | Thermal expansion has nowhere to go | Install/replace expansion tank | $150 – $450 |
| High inlet pressure (>80 psi) | Bad or missing pressure‑reducing valve | Add/adjust PRV to 50 psi | $250 – $450 |
| Sediment “kettle‑boil” | Minerals blanket the burner, overheating water | Flush 2 – 3 gal; install filter | $0 – $200 (flush) |
| Leaky drain valve | Plastic valves loosen or crack | Replace with brass | $10 part / $80 labor |
| Tank seam or internal crack | Steel has corroded | Replace heater | $882 – $1,807 (avg. $1,328) |
Five‑Step Safety Check You Can Do Right Now
- Kill the heat. Flip the breaker or set the gas control to “pilot.”
- Shut the cold‑water supply valve.
- Dry‑towel test around the T&P valve, drain cock, and seams.
- Lift and snap the T&P lever; a brief gush should stop once you release it.
- Screw on a $15 pressure gauge to the hose bib or drain cock. Read the static pressure after an hour with no water running.
If pressure sits above 80 psi or the lever continues to drip, move to the fixes below.
Simple Fixes Most Homeowners Can Handle
- Swap the T&P valve. A brass ¾‑inch valve costs $20; a plumber visit tops at $200.
- Add or recharge an expansion tank. Pre‑pressurize it to match your cold‑water pressure (usually 50 psi).
- Install/adjust a PRV. Turn the screw clockwise to lower pressure; verify with the gauge.
- Flush sediment. Drain two gallons twice a year—more often if you live in hard‑water Orlando (check our water‑heater troubleshooting guide).
- Tighten/replace the drain valve. Wrap new valve threads with Teflon tape; hand‑tighten plus a quarter‑turn with a wrench.
These fixes cost far less than a flooded hallway or a scalding burst.
When to Call Pros
Contact The Romans Plumbing if you notice:
- Water pouring (not dripping) from the overflow pipe.
- Rusty discharge or visible tank seam leaks.
- A rotten‑egg odor or any sign of gas around a gas heater.
- Pressure readings that climb back over 80 psi after adjustments.
Replacing a relief valve is cheap; ignoring a cracked tank risks a $1,300 replacement and potential drywall repairs.
Preventing the Next Leak
| Month | Task |
| January & July | Flip the T&P lever for two seconds |
| March | Flush two gallons from the tank |
| May | Inspect anode rod (replace if <½‑inch) |
| September | Gauge test house pressure |
| November | Check expansion‑tank air charge |
Stick this mini‑calendar inside a cabinet door (and bookmark our plumbing checklist for new homeowners for more):
Need professional service? Our Orlando team offers same‑day tune‑ups—learn the typical water‑heater lifespan and schedule your maintenance visit.
And if you’re ready for peace of mind, book a no‑pressure diagnostic today with us, keeping water heaters safe, quiet, and leak‑free.
FAQs | Hot Water Heater Release Water
Why does my hot water heater release water only after long showers?
Extended heating cycles raise both pressure and temperature. If you lack an expansion tank—or your house pressure creeps above 80 psi—the T&P valve will vent a few ounces to stay below its 150 psi/210 °F limit.
Can I cap the overflow pipe to stop the leak?
No. Capping violates plumbing code and turns a safety device into a bomb risk. Replace the T&P valve or install a pressure‑reducing valve instead.
How often should I replace the T&P valve?
Manufacturers recommend testing twice a year and replacing every five to seven years—or immediately if it drips continuously. Parts are inexpensive; labor runs about $200.
