My hot water tank is leaking! Now what?

A leaking hot water tank can feel urgent fast, especially when the first sign is water showing up in a tenant suite in the middle of the night. In that moment, it is easy to assume the tank itself has failed. But that is not always the case.

When water appears at the bottom of a commercial hot water tank, the source of the leak is often somewhere else. Because these tanks are usually wrapped in thick insulation, water can travel behind the insulation and show up far from where it actually began. That is why the first step is to stay calm and determine where the leak is really coming from.

Start by checking the piping connected to and above the tank. This is one of the most common places for leaks to begin. A small leak in the piping can run down behind the insulation and collect at the base of the tank, making it look like the tank is leaking when it is not.

If the piping appears dry, look at the pressure relief valve and the hot water outlet connections at the top of the tank. Leaks in these areas are also common, especially where there are corroded nipples, flanges, or unions. Again, water from above can travel downward behind the insulation and appear at the bottom.

From there, inspect the other couplings and tank connections along the shell of the tank. In some cases, the insulation may need to be pulled back or cut open to get a better look. The manway cover and drain connection should also be checked. If no obvious source can be found, insulation may need to be removed from the tank so the leak can be traced properly.

Once the source of the leak has been identified, the next step depends on where it is coming from. If the issue is in the piping, a plumber can usually address the repair. If the leak is coming from the tank itself, the tank may need to be isolated and assessed. In buildings with more than one tank on the loop, it may be possible to take one tank offline temporarily and continue operating with reduced capacity until repairs are made.

Not every tank leak means full replacement. If the leak is coming from a coupling or flange, a repair may be possible with limited downtime. If the leak is coming from the tank wall, the condition of the tank as a whole should be assessed before deciding on the next step.

The most important thing is not to guess. What looks like a failed tank can sometimes be a plumbing issue, and what looks minor on the outside can point to a larger problem hidden behind the insulation. Finding the true source of the leak is what allows the right repair to happen next.