Hot Water Tank Leaks: What You Can Do

A leaking hot water tank can damage flooring, drywall, mechanical rooms, and nearby storage. These steps help Calgary homeowners reduce risk while deciding whether the tank needs repair or replacement.

Turn Off the Water Supply

If water is actively leaking, shut off the cold water supply valve above the tank. If the valve is stuck or water continues to spread, call a plumber right away.

Shut Down the Energy Source Safely

For a gas water heater, follow the manufacturer instructions on the gas control valve and do not continue if you smell gas. For an electric water heater, turn off power at the breaker before touching the unit or nearby water.

Find Where the Leak Is Coming From

Water near the top of the tank may come from a fitting, valve, or supply line. Water from the bottom, rust around the base, or repeated pooling can mean the tank itself is failing.

Do Not Ignore Rust or Repeated Leaks

A small leak can become a larger emergency. If the tank is older, rusty, noisy, producing discoloured water, or no longer keeping up with demand, replacement may be the safer long-term option.

Why Hot Water Tanks Leak: The Five Most Common Causes

Understanding what is causing the leak determines whether you need a quick repair or a full replacement. These are the most common failure points on Calgary hot water tanks.

1. Pressure Relief Valve Dripping

The pressure relief valve (PRV) is a safety device that releases water when pressure or temperature inside the tank gets too high. A PRV that drips occasionally may be responding to normal pressure spikes — but one that drips constantly is either doing so because internal pressure is chronically elevated, or because the valve itself has worn out and can no longer seal properly. Either situation needs attention. A non-functional PRV cannot protect your tank during a genuine pressure event.

2. Drain Valve Seeping

The drain valve at the bottom of the tank is used for flushing sediment during maintenance. Most are plastic and degrade over the years. A slow drip from the drain valve can often be fixed by tightening it a quarter turn. If it continues, the valve can be replaced without swapping the full tank — a straightforward repair that costs far less than replacement.

3. Loose or Corroded Inlet and Outlet Fittings

The cold water inlet and hot water outlet connections at the top of the tank can develop slow leaks at the joints, especially on older tanks where dielectric unions have corroded or where connections have shifted over years of thermal expansion and contraction. Water appearing near the top of the unit with no other explanation usually points here.

4. Depleted Anode Rod

The anode rod is a sacrificial metal rod that attracts corrosion so the inside of the tank does not corrode instead. Once the anode rod is fully depleted, the tank walls begin to corrode directly. The tank will eventually develop pinhole leaks from the inside out. By the time this is happening, the anode rod has been exhausted for years and replacement is the only option.

5. Tank Body Failure

Internal corrosion, manufacturing defects, or severe sediment damage can cause the tank body itself to leak. Rust-coloured water, visible rust around the base, or pooling water with no identifiable external source all point to internal tank failure. A leaking tank body cannot be reliably repaired — it needs to be replaced before it fails completely and causes serious water damage.

Why Calgary Homes Get More Sediment Buildup

Calgary’s municipal water supply is classified as hard water. It carries a high concentration of dissolved calcium and magnesium compared to most major Canadian cities. Over time, these minerals settle at the bottom of the hot water tank as a layer of sediment.

That sediment layer creates compounding problems: it insulates the burner or heating element from the water (raising energy costs and putting stress on components), it retains heat against the tank lining and degrades it faster, and it creates conditions that accelerate corrosion. A hot water tank in Calgary that is never flushed will fail faster than the same tank installed in a soft-water city.

Flushing the tank annually removes accumulated sediment and meaningfully extends tank life. If your tank has never been flushed and is more than five years old, scheduling a maintenance flush before a leak forces the issue is money well spent.

Repair or Replace? How to Decide

Not every leak means a new tank. Use the following as a general guide:

• Under 8 years old, leak from a valve or fitting: Repair is almost always the right call. Parts are inexpensive and the tank has years of service remaining.
• 8–12 years old, leak from a fitting: Repair is reasonable, but have your technician assess the overall tank condition at the same visit — particularly the anode rod status and signs of internal corrosion.
• 10+ years old, leak from the tank body or base: Replace. Patching an internally corroded tank only delays the inevitable, and a full tank failure can cause significant structural water damage.
• Any age, rust-coloured water or repeated leaks: Replace. Once internal corrosion has progressed to this point, the tank will not hold long-term regardless of what repairs are made.

Frequently Asked Questions

How long does it take to drain a hot water tank?

A standard 40–60 gallon tank takes 20 to 45 minutes to fully drain depending on the drain valve condition and how much sediment is restricting flow. Direct the drain hose to a floor drain or outside, and do not leave the process unattended.

Is a dripping pressure relief valve dangerous?

It depends on the cause. A PRV releasing intermittently because pressure inside the tank is elevated is doing its job — but that elevated pressure needs investigation. A PRV that drips constantly may be worn out and no longer functional. Have it looked at promptly either way, since a non-functional PRV is a safety risk.

How much does hot water tank replacement cost in Calgary?

Costs vary based on tank size, fuel type (natural gas, electric, or power vent), and installation complexity. A standard natural gas storage tank replacement in Calgary typically runs between $1,200 and $2,200 fully installed. Tankless water heaters cost more upfront but can reduce energy costs significantly over their lifespan.

Can a leaking hot water tank be covered by home insurance?

Most standard home insurance policies cover sudden and accidental water damage, but not gradual leaks that developed over time due to age or deferred maintenance. If your tank fails suddenly and causes water damage, document everything immediately and contact your insurer. A written plumber’s report noting the cause of failure can support your claim.

How quickly can ER Plumbing & Heating respond to a hot water tank leak?

For active leaks causing water damage, we offer same-day and emergency response across Calgary. Call 587-777-3164 and describe the situation — we will advise on immediate steps and confirm the earliest available technician.

Book Hot Water Tank Service
ER Plumbing & Heating handles hot water tank repair and replacement across Calgary, including emergency leaks, same-day service when available, and clean installation of properly sized tanks. Call 587-777-3164.