A puddle beside a water heater makes a failed tank seem like the obvious answer. Sometimes that is exactly what happened, but water often starts much higher up, runs down the jacket, and collects at the floor.
The first job is not to take anything apart. It is to find where the water starts and decide whether it is safe to stay near the equipment.
Step away from electrical or gas hazards first
If an electric water heater is surrounded by water, do not stand in the wet area to reach a switch. If power can be shut off from a dry, safe location, do so. Otherwise, call for help.
A gas odor is a separate emergency. Leave the area, avoid operating switches or creating sparks, and follow the emergency instructions from your gas utility or local authorities.
Dry the area so the leak can reveal itself
If conditions are stable, dry the floor and outside of the heater. Then watch for the first place that gets wet again. Check the cold- and hot-water connections at the top, nearby piping, flexible connectors, and visible threaded joints.
A tiny drip at the top can travel down the side of the tank and make the bottom look like the source.
The drain valve can leak
Tank-style heaters usually have a drain valve near the bottom for maintenance. If the outlet itself is wet, the valve may be the issue rather than the tank.
Do not simply tighten an old plastic or corroded valve harder. Forcing a weakened part can turn a small drip into a larger leak.
Relief-valve discharge is different
Tank heaters also have a temperature-and-pressure relief valve. Its discharge pipe is a safety path. If water is coming from that pipe, do not cap, plug, or disable it.
Pressure, thermal expansion, temperature, or a faulty valve can all play a role. That situation needs proper diagnosis rather than a blocked discharge line.
Could it be condensation?
Some heaters can produce temporary condensation under certain operating conditions, especially with very cold incoming water. Light, short-lived moisture is different from a puddle that keeps growing.
Dry the area and note when the moisture returns: after a large hot-water draw, only during burner operation, or continuously even when the heater has been idle. The timing is useful evidence.
Water from the tank base is the serious scenario
If fittings, valves, and nearby plumbing stay dry but water appears to come from the tank shell or bottom, internal corrosion or a tank failure becomes more likely.
Rheem notes that pooling water at the base can be a sign of tank deterioration. A leaking storage tank is generally replaced rather than patched from the outside.
Limit damage without creating a new hazard
If you know the installation and can do so safely, closing the heater’s cold-water supply can limit an active leak. Shut down the energy source according to the unit’s instructions as well. Do not drain a hot tank casually; the water can cause severe burns.
Take photos of the leak, model plate, and visible corrosion. The puddle shows where water ends up; the first wet point usually tells you what actually failed.
Sources
- Rheem — What to Do Before Calling a Plumber or Replacing Your Water Heater — Guidance on visible leaks, corrosion, sediment, condensation, and signs that warrant service.