Top 3 Causes of a Water Heater Leak from the Bottom

Leaking water heater

When a water heater leaks, it’s usually from one of the places — the top or the bottom.

Leaks from the top are no biggie, usually involving a valve replacement or tightening of the water lines.

Leaks from the bottom are more concerning. They could be due to:

  1. A loose valve;
  2. Condensation;
  3. A problem with the water tank.

Let’s hope for your sake it isn’t Door Number 3.

Whatever the source, you should take the leak seriously. Fix it DIY if you can; call the plumber if you can’t. Leaks can damage flooring and objects stored nearby, and go from trickles to torrents in short order.

Standard water heaters may last 10 – 15 years. Orange County’s notoriously hard water takes a few months off the life of any appliance that comes in contact with it.

So if your water heater is approaching the 10-year mark, you may consider replacing it with a tankless heater that lasts twice as long and provides almost unlimited hot water on demand.

In the meantime, here’s how to troubleshoot that leak.

Reasons for a Hot Water Leak from the Bottom of the Tank

1) A Loose Drain Valve

All tanked water heaters have a drain valve. This brass or plastic valve looks like a water tap and sits at the base of the heater for good reason.

The drain valve lets you empty the tank periodically (at least 1 per year is our recommendation) to remove sediment buildup that degrades heater performance and water quality.

The drain valve should be closed tight, and the base of the valve should have a watertight seal with the tank.

Sealing the valve is an easy enough DIY repair, or even replacing it if need be.

2) Water Condensation

Condensation creates “phantom leaks” — the appearance of leaks, but no actual leaking.

Condensation forms when the temperature of the water inside your heater’s tank falls well below the temperature of the surrounding air. This situation is rare for a water heater but can happen when hot water is exhausted (by the teen taking the 40-minute shower) and very cold water enters the tank from outside lines.

Condensation may drip down the side of the heater and leave water spots that mimic a small leak.

3) An Aging Water Heater with a Corroded Tank

There’s no consensus on the lifespan of a water heater. Estimates vary from 7-15 years, but you can bet that 15 years is the upper limit.

Beyond 10 years of use, you should expect increasing problems, corrosion being the most serious.

Several factors influence water heater life:

  • The unit’s brand and design
  • The water heater’s location
  • The quality of your local water supply
  • How well the unit has been maintained
  • The skill of the plumber who installed the unit

Once the water tank corrodes, your only option is to install a new heater and be quick about it.

Small leaks in the tank are warning signs of impending failure, where the water heater can release many gallons of water into your home, garage, or wherever it’s located.

Orange Coast Plumbing offers free estimates for water heater installation and guarantees all work. Call us today if you suspect your heater has begun its transition to the afterlife. We’ll install a new, energy-efficient unit for you, and haul your old heater to the recycling yard where it can be among friends.



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(714) 953-1111


1506 N Clinton St., Santa Ana, CA 92703
Service offices located throughout Orange County

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