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Why You Should Flush Your Hot Water Tank Every Year (And How to Do It Safely)
If your tank sounds like popcorn, that's not "character"—it's sediment. Calgary's hard water drops minerals into the bottom of your tank, forming a crust that eats efficiency, overheats the metal, shortens lifespan, and turns showers lukewarm. A simple annual flush can add years to your tank and keep bills lower. Here's the no-nonsense homeowner playbook.
Quick Wins (TL;DR)
1
Do it yearly
Do it yearly in Calgary. Hard water = more sediment.
2
Safety first
Shut power/gas off first, and let the water cool.
3
Protect the T&P valve
Don't remove the T&P valve (safety device). Use the drain valve at the bottom.
4
Consider replacement
If the tank is 12+ years old and never flushed, consider replacement instead of flushing—heavy sediment can clog valves or start leaks.
What You'll Need
Essential Tools
  • Garden hose (female end fits tank drain)
  • Bucket or nearby floor drain
  • Flathead screwdriver (metal drain valves)
  • Towels / rags
Optional Items
  • Pliers (stubborn caps)
  • Vinegar (for stubborn sediment)
  • Anode socket if you're inspecting the rod
Safety First (Read This)

Electric tanks: Turn off the double-pole breaker. Elements must not run dry.

Gas tanks: Turn gas control to OFF (or pilot on older models) and shut the gas valve if you're unsure.

Let the tank cool 2–3 hours to avoid scalding.

Don't cap or plug the T&P valve—ever. If it drips constantly, book a service call.
Step-by-Step: How to Flush a Gas or Electric Tank
01
Power Down & Cool
  • Electric: breaker OFF.
  • Gas: set control to OFF/Pilot.
  • Wait until the tank is warm, not hot.
02
Close Cold Water Inlet
Shut the cold valve on the pipe entering the top of the tank.
03
Attach Hose to Drain Valve
  • Bottom of tank → garden hose → floor drain or bucket.
  • If there's a plastic cap on the drain, remove it.
04
Open a Hot Tap Upstairs
Crack a nearby hot faucet to prevent vacuum lock and help draining.
05
Open the Tank Drain Valve
  • Use screwdriver/hand-turn knob.
  • Let it drain until flow slows.
Power Flush & Refill Process
Power Flush
  • Close the drain briefly.
  • Open the cold inlet for 15–30 seconds, then reopen the drain.
  • Repeat 3–5 cycles until water runs clear. (In Calgary, first flush is usually cloudy/grey with grit.)
Close Drain, Refill, Bleed Air
  • Close the drain valve firmly.
  • Open the cold inlet fully to refill.
  • Leave the hot tap open until it stops sputtering and flows smoothly.
Leak Check
Inspect drain valve, unions, and top fittings. Tighten gently if needed.
Restore Power/Gas
  • Electric: only after the tank is full (hot tap runs steadily), turn breaker ON.
  • Gas: relight/turn control to ON per the label instructions.
Total time: 30–45 minutes if everything cooperates.
When Not to Flush (or to Call a Pro)
Very old tank (12+ years) never flushed
Sediment can be holding tiny leaks together. Flushing may expose them. Consider replacement.
Drain valve clogged/no flow
Forcing it can break the valve. Call a pro; they can use pump/vacuum methods.
Persistent T&P valve drip
Indicates pressure/temp issue. Do not cap—book service.
The Anode Rod: Your Tank's Bodyguard
Calgary's water chews through anode rods. Check/replace every 3–5 years:
  • Top of tank under a hex head (often 1–1/16").
  • If it's under ½" thick or coated in calcium, replace it.
  • Consider powered or segmented (flex) anodes for low-clearance basements.
Winter Notes for Calgary
If your tank vents through PVC (power/direct vent), check exterior terminations for snow/ice.
Never pour hot water into vent pipes—it runs back into the inducer motor and kills it. Brush snow away and let it thaw.
Annual Maintenance Schedule & Costs
Annual Maintenance Schedule (Simple)
1
Spring
Flush tank, test T&P valve, check for leaks/corrosion.
2
Every 3–5 years
Replace anode rod.
3
Anytime
Install a $30 leak alarm near the base—cheap insurance for finished basements.
What a Pro Service Typically Costs (Calgary)
Troubleshooting & Related Resources
Troubleshooting After a Flush
No hot water (electric)
You may have powered on before the tank was full and tripped an element. Turn power off, let it cool, press the upper reset (red button), refill fully, then power on.
Pilot won't stay lit (gas)
Could be a thermocouple/gas control. Time to call a pro.
Drain valve dripping
Mineral bits in the seat. Try closing more firmly; if it persists, replace the valve.
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