First, Confirm It Is Actually Leaking
Before you assume the worst, rule out condensation. On a newly filled tank, or during a cold snap in the Lower Mainland, cold incoming water can chill the outside of the tank below the dew point, and the resulting droplets run down to form a small puddle. This is common in unheated Greater Vancouver basements, crawlspaces, and garages.
To test, dry the tank and the floor completely with a towel, then watch for 30 to 60 minutes with the heater running. Condensation reappears slowly as a fine film across the whole bottom. A real leak produces a defined trickle from one spot or a puddle that keeps refilling no matter how often you wipe it. If the water returns fast, you have a genuine leak that needs attention.
The Four Most Common Causes
1. Drain valve at the base. The small spigot near the floor is the most frequent culprit. A worn washer, a loose handle, or a valve that was bumped can weep steadily. This is often a repairable part rather than a tank failure.
2. Temperature & Pressure (T&P) relief valve discharge. The T&P valve has a pipe that runs down toward the floor. If the valve is releasing because of excess pressure or temperature, water exits the bottom of that pipe and looks like a base leak. The problem is upstream, not the tank shell.
3. Loose or corroded inlet/outlet connections. The hot and cold lines on top can drip down the tank body and collect at the base, mimicking a bottom leak. Always trace water upward to its true origin before concluding the tank has failed.
4. A corroded, perforated tank. When the steel tank itself rusts through from the inside, water seeps out of the very bottom of the jacket — not from a fitting. This is the one cause that cannot be repaired. Once the inner tank is breached, replacement is the only safe option.
How to Tell a Repairable Leak From a Dead Tank
Trace the water to its source. If it originates at the drain valve, a connection, or the T&P discharge pipe, the tank shell is likely intact and the fault can usually be repaired or the part replaced.
If water is genuinely emerging from the seam at the very bottom of the steel jacket — with no fitting above it — the tank has rusted through. There is no patch, epoxy, or weld that safely restores a domestic hot water tank under pressure. The internal glass lining has failed, corrosion is advancing, and a slow seep today can become a sudden flood. At that point, plan for replacement promptly.
What to Do Right Now
If the leak is small and traced to a fitting, you can often manage it until a technician arrives. If water is flowing steadily or pooling fast, shut off the cold water supply valve at the top of the tank by turning it clockwise, then turn off the gas control to the pilot setting (or switch off the breaker on an electric unit) to protect the burner and elements.
Mop up standing water to prevent damage to flooring and adjacent walls — Greater Vancouver basements are prone to moisture problems, and a slow leak left alone can encourage mold.
Tank water heaters are serviced by our parent company, CanroHeat. Whether the fix is a new drain valve or a full tank replacement, call 604-359-1081 for a straight assessment and an exact quote — no guesswork, no upsell.