Your water heater leaking from the bottom usually has one of three explanations, ranging from trivial to terminal.
First, the drain valve may be dripping, either because it was not fully closed after a flush or because the plastic valve body has degraded; swapping it for a brass valve is inexpensive.
Second, water escaping from a fitting or the relief valve higher up can run down the tank exterior and collect at the base, so trace the path carefully before assuming the worst.
Third, and most serious, the inner steel tank may have rusted through after the sacrificial anode rod was fully consumed.
Tank failure produces steady seepage that worsens over days and cannot be patched or welded.
Gas units may also show harmless condensation during heavy use.
Persistent bottom leaks on a heater older than a decade almost always mean replacement.
