Water heater leaking around the anode rod
Likely a repair
The anode rod screws into the top of the tank under a hex-head plug, sometimes hidden beneath a plastic cap in the insulation. A leak around it is the gasket or the thread sealant, not a tank failure — and the tank itself is still sound.
How to tell it's this
- The wet spot is a hex plug on the tank top, not a pipe.
- It often follows recent work — the rod was inspected or replaced in the last year.
- Water seeps from the threads rather than running from a joint above.
- Lifting the insulation cap shows water sitting in the recess.
What to do
- Shut off the cold water and run a hot tap to relieve pressure before anything else.
- Have a plumber reseal or replace the rod. A seized rod can take the tank fitting with it, which is why this is not a good first DIY job.
- Ask them to check the rod's condition while it is out. A rod eaten down to the wire means the tank has been corroding unprotected, and the tank is on borrowed time.
- If the unit is past 8 years and the rod is gone, price a replacement alongside the repair.
What it costs
With a plumber
Replace the anode rod
$200–$400
installed
Part only
If a pro is already on site
$30–$70
the part itself
Typical US ranges for 2026, not quotes. Labour is 30–50% of an installed price, so where you live moves these numbers more than anything else does. Get two or three local estimates.
If that's not it
The wet spot is a pipe, not a hex plug
A pipe or nipple at the top →
Water is pooling under the tank as well
A tank that has rusted through →
Not sure which of these it is?
Answer four questions — where it's leaking, tank or tankless, gas or electric, and how
old it is — for a specific cause, a repair-or-replace call, and a cost.