Water, Plumbing and Drains
Water does the most damage of anything in a house, and usually starts small. This page covers your main shut-off, the water heater and scald safety, the sump pump, backwater valves and sewer backups, finding hidden leaks with the water meter, running toilets, slow drains without harsh chemicals, and when to call a licensed plumber.
On this page
Know your main shut-off
If a pipe bursts, the most important thing you can do is stop the water, fast. That means knowing exactly where the main shut-off valve is before you need it.
- Where it is: the City of Lethbridge says your water meter is located just above the main water shut-off valve in your home. The City of Calgary describes the valve as usually in the basement near the floor, on the pipe where the water line enters the house, often close to the water heater.
- Exercise it. CMHC’s winter checklist says to test plumbing shut-off valves so they don’t seize. Turn the main valve off and back on once a year, and do the same with the small valves under sinks and behind toilets.
What it means for you: tie a bright tag on the valve. If it’s stiff, corroded or drips when you turn it, have a plumber replace it now, not during an emergency. For a problem on the City’s side, such as no water pressure or water pooling in the street, the City says to call 311, which it says handles water and wastewater emergencies.
The gas and power shut-offs are on the Home Maintenance hub.
The water heater
Drain a little sediment
Lethbridge water is on the hard side: the City’s water treatment plant reports have measured hardness of about 145 to 158 mg/L, and Health Canada says hardness minerals form scale inside water heating appliances. CMHC’s winter checklist says to drain a dishpan of water from the clean-out (drain) valve near the bottom of the tank, following the owner’s manual. The water that comes out is hot, so use a pail, not your hands, and keep children well back.
Test the relief valve
Every tank has a temperature and pressure relief valve, a safety valve that lets water out if the tank gets too hot or the pressure too high. CMHC’s spring checklist says to test it following the manual, and warns that this may release scalding water. If you’re not comfortable doing that, ask for it at the next service. If the valve drips all the time, call a plumber.
Set a safe temperature
Hot tap water burns quickly, especially for young children and older adults. Parachute, Canada’s national injury prevention charity, says:
- The hot water at your taps should be no hotter than 49°C (120°F). At 60°C, water can cause a third-degree burn on a child’s skin in one second; at 49°C it takes about 10 minutes.
- Older adults are also at high risk, partly because their skin may not feel heat quickly.
- Electric water heaters: don’t lower the tank setting below 60°C, because the bacteria that cause Legionnaires’ disease can grow more easily in some electric tanks. Instead, a plumber can install a mixing (tempering) valve that keeps water at the taps at or below 49°C while the tank stays hotter.
- Gas or oil water heaters: Parachute says to turn the dial to the Warm or Medium setting, and not to go below 49°C or Medium.
- Check it at the tap. Parachute suggests filling a cup with hot water from the tap, putting a meat or candy thermometer in it and reading it after 30 seconds. If it’s higher than 49°C, the water is too hot.
Vents and permits
A gas water heater vents like a furnace, often through the same kind of side-wall pipe. Keep its vent clear of snow (see outside vents). The City of Lethbridge says installing a new water heater needs a gas permit, which only licensed gasfitters can get, and that replacing a tank may also need a plumbing permit if it changes the water or drain piping or the venting.
The sump pump
A sump pump sits in a pit in the basement floor and pumps out water that collects around the foundation. The City of Lethbridge says sump pumps are common in Lethbridge basements, and its advice before a stormy forecast is to check your sump pump.
- Test it in the fall and again before the spring thaw. CMHC’s schedule says to test the sump pump and its discharge line each fall, and to make sure it works before the thaw. Following the manual, slowly pour a pail of water into the pit and watch the pump switch on, empty the pit and switch off.
- Check where the water goes. CMHC says the discharge should drain away from the foundation. The City’s design standards say sump pump outlets should discharge no closer than 1.0 m from the property line, so you’re not sending your water onto a neighbour’s yard.
- Never into the sanitary sewer. The City’s design standards say sump pump and weeping tile water must not go into the sanitary sewer. Don’t run a sump hose into a floor drain or laundry tub. The City’s stormwater and wastewater page says many homes built in newer neighbourhoods since 2005 have their sump connected underground to the storm system instead.
Spring snowmelt and heavy summer thunderstorms are when sump pumps work hardest. When the forecast shows a big melt after a snowy spell, or a severe thunderstorm watch, check that the pump runs and the outside discharge is clear before the water arrives.
Frozen pipes and outdoor taps
Our Winterizing your home page has the full steps for keeping pipes from freezing, and what to do if one does (shut off the water, open the nearest tap, gentle heat only, never an open flame).
- Heat tape and heat cables: the City of Lethbridge’s frozen water lines advice suggests looking for pipe sleeves, heat tape or heat cables on pipes at risk. Follow the manufacturer’s instructions exactly, check them each fall, and replace any that are damaged or worn.
- Outdoor taps: the City’s advice includes turning off the water line to outside faucets. Shut off the inside valve, disconnect the hose and drain the tap before freeze-up. The step-by-step is on Hoses, sprinklers and outdoor taps.
Backwater valves and sewer backups
A backwater valve sits on the main sewer pipe leaving your house. Normally wastewater flows out to the City sewer. If the sewer backs up, for example in a very heavy rainstorm, the valve’s flap closes automatically so sewage can’t flow back into your basement. (It’s different from the backflow preventer on a garden hose or irrigation system, which protects the drinking water. That’s covered on Hoses and outdoor taps.)
- Do you have one? If you’re not sure, a licensed plumber can tell you.
- The City of Calgary recommends a backwater valve on fixtures below ground level, such as basement toilets, showers and floor drains, to help prevent costly sewage damage.
- Keep it working. Edmonton’s water utility calls inspecting a backwater valve essential home maintenance. With gloves and eye protection, remove the access cover, look for debris around the flap, flush the area with water, check that the flap moves freely and look at the seal. Put the cover back on. Deeper cleaning may need a qualified contractor.
- When it’s closed, the same utility says not to use the toilet, sink, shower, washer or dishwasher, because that water has nowhere to go.
The City of Lethbridge’s water and sewer pages don’t currently give specific guidance on backwater valves, so ask a licensed plumber whether one makes sense for your home. Installing one changes the drainage piping, which the City says needs a plumbing permit.
If the sewer backs up
- Stay out of the water if it could reach outlets, cords, appliances or the furnace. Water conducts electricity, and a shock in water can kill. If you can’t reach the electrical panel without stepping into water, don’t try. Ask the electric utility to disconnect the power (see who to call). Once it’s safe, wear rubber gloves, boots and a mask, because the City of Calgary warns that sewage can carry harmful bacteria.
- Call 311. The City of Lethbridge asks residents to call 311 for a sewer backup. It says it will send someone to investigate if it can’t help over the phone, and that emergency coverage is available 24 hours a day.
- Call your insurer as soon as you can, and take photos before you clean up.
- Leave the panel and appliances alone. The Government of Alberta says not to shut off electricity if any water is present, to ask your electricity supplier how to make equipment safe, and not to touch the electrical panel or use appliances after flooding until a qualified electrician has cleaned, dried and inspected them.
The City of Lethbridge says the sewer line from your house to the property line is the homeowner’s responsibility, and the City looks after the part from the property line to the street.
Finding hidden leaks with the water meter
A leak inside a wall or under a floor can run for weeks before you see a stain. Your water meter can tell you if water is going somewhere it shouldn’t. The City of Calgary’s high water use checklist gives this test:
- Turn off everything that uses water, inside and out: taps, toilets, the washer, dishwasher, humidifier, water softener and irrigation. Make sure nobody runs water during the test.
- Don’t touch the main valve. Leave it open; you’re testing the pipes beyond it.
- Find the meter. In Lethbridge, it’s just above your main shut-off.
- Watch the flow indicator. It may look like a small triangle, gear or needle. If it’s still turning with everything off, water is leaking somewhere in the house.
Calgary’s checklist says a slow-moving indicator can mean a dripping tap or a humidifier that isn’t working properly, and a fast-moving one can point to a toilet flapper that isn’t closing. If you can’t find the leak, call a plumber; anything behind a wall or under a floor is their job.
What it means for you: if a utility bill is higher than usual, Calgary’s checklist is a good place to start. Do the meter test before you go away for more than a few days, and when you get back.
Running toilets and dripping taps
A toilet that runs, hisses or refills on its own is wasting water all day. The City of Lethbridge says a leaky toilet can leak up to 1,000 litres of water a day.
The food colouring test
The City of Calgary’s checklist suggests putting several drops of food colouring in the toilet tank (not the bowl) and waiting 10 minutes without flushing. If colour shows up in the bowl, the toilet is leaking. Calgary lists flappers that don’t close among the causes. Replacing a worn flapper is routine maintenance and doesn’t need a permit.
Dripping taps
CMHC’s winter checklist says to check faucets for drips and replace washers as needed.
Replacing an old toilet? As of November 2026, the City of Lethbridge’s Environmental Incentive Program is taking applications until noon on December 31, 2026, or until its funding runs out. It offers rebates, credited to your water account, to Lethbridge residents with a residential water account who install a toilet rated 6 litres per flush or less. Condo and apartment residents whose water is included in condo fees don’t qualify. Read the program terms on the City’s website before you buy, because purchase dates and other rules apply.
A toilet tank holds clean water that waits for the next flush. A rubber flap at the bottom keeps it in. If the flap doesn’t seal, water sneaks into the bowl all day long.
Wonder: how could you tell if water is sneaking out if you can’t see it moving?
Try this: be a leak detective. With a grown-up, add a few drops of food colouring to the tank (the part with the lid at the back, never the bowl). Set a timer for 10 minutes and don’t flush. If the bowl water changes colour, you’ve found a leak. Flush afterwards so the colour doesn’t stain.
Slow drains, without harsh chemicals
Most slow drains are caused by things that shouldn’t be there: grease, hair and items that don’t break down. The City of Calgary says cooking fats, oils and grease are the main cause of wastewater blockages and backups. Hot, soapy water doesn’t help, because sewer pipes in the ground are cold and the grease hardens further along.
Prevention first
- Grease: let it cool and harden in a container, and wipe pans and scrape plates before washing. The City of Lethbridge’s green cart takes solid fat, cooking oil and cooking grease.
- Strainers: use a kitchen sink strainer, and a hair catcher in the tub and shower. Put the hair in the garbage.
- Only toilet paper in the toilet. Wipes, including “flushable” ones, paper towels, tissues, dental floss and hygiene products go in the garbage. Calgary says flushable wipes keep their shape and strength and don’t break down in pipes. The City of Lethbridge also asks residents not to flush wipes, fats, oils, grease and hair.
- Keep traps full. CMHC suggests running water in fixtures you rarely use, like a spare shower or laundry tub, and checking that the basement floor drain trap holds water.
Clearing a slow drain
- Clean the stopper and strainer. Many bathroom sinks and tubs slow down because of hair caught on the stopper. Pull it out and clean it.
- Use a plunger. It’s the simplest tool for a clog, and uses no chemicals at all.
- Try a hand drain snake (a small auger) for clogs a plunger won’t move.
- If it still won’t clear, or more than one drain is slow at once, call a plumber.
Skip the chemical drain cleaners. Health Canada lists drain cleaners among the household chemicals that can be dangerous, and says corrosive products can burn your skin or eyes and damage your throat and stomach if swallowed. It also says never to mix household chemical products, because some mixtures produce harmful gases. That includes pouring a second product on top of a drain cleaner that didn’t work. If you have old drain cleaner at home, Calgary notes that cleaners and chemicals count as household hazardous waste; take them to the Hazardous Waste area at the City of Lethbridge’s Waste & Recycling Centre rather than pouring them down the drain.
When to call a licensed plumber
The shut-off, the meter test, flappers, washers, strainers and plungers are yours to do. Call a licensed plumber or gasfitter for:
- Anything involving gas: gas water heaters, gas lines or appliance connections. The City says only licensed gasfitters can get gas permits.
- Installing or replacing a water heater, and a relief valve that drips constantly.
- Anything behind walls or under floors, including a leak you’ve found with the meter but can’t see.
- Sewer backups, after you’ve called 311, and backwater valve installation.
- Burst pipes: shut off the main first, then call.
- Work that needs a permit. The City of Lethbridge says installing, extending, altering or replacing a plumbing system, adding fixtures, and replacing sewer connections need a plumbing permit. Homeowners can apply only if they live (or will live) at the property and can show they’re competent to do the work to code. Routine maintenance and like-for-like fixture swaps, such as a faucet, don’t.
When you hire anyone, get written quotes and a written contract. The City suggests getting at least two quotes for sewer line replacement. See hiring after a storm for the Government of Alberta’s tips on contractors.
Sources
- City of Lethbridge, Water, wastewater and stormwater (meter above the main shut-off; call 311 for water and wastewater emergencies): lethbridge.ca
- City of Lethbridge, Stormwater and wastewater (sewer problems and 311; owner’s side of the sewer line; sump pumps; what not to flush): lethbridge.ca
- City of Lethbridge, Frozen water lines (heat tape and cables; outside faucets): lethbridge.ca
- City of Lethbridge, Design Standards 2021, Section 9: Post lot development issues (sump outlets 1.0 m from property line; downspouts): lethbridge.ca
- City of Lethbridge, Design Standards 2021, Section 5: Sanitary sewer (no sump or weeping tile water in the sanitary sewer): lethbridge.ca
- City of Lethbridge, Water conservation (leaky toilets up to 1,000 litres a day): lethbridge.ca
- City of Lethbridge, Environmental Incentive Program (open April 22 to December 31, 2026, or until funding runs out; checked 2026-11-01): lethbridge.ca
- City of Lethbridge, Plumbing permits: lethbridge.ca
- City of Lethbridge, Gas permits (water heaters; licensed gasfitters only): lethbridge.ca
- Lethbridge Herald, City has tips for dealing with stormy forecast (June 21, 2025) (check your sump pump; call 311 for sewer backups): lethbridgeherald.com
- Canada Mortgage and Housing Corporation, About Your House: Home Maintenance Schedule (shut-off valves; water heater; sump pump; traps; faucets): assets.cmhc-schl.gc.ca
- City of Lethbridge, Water Treatment Plant quarterly water quality summaries (hardness 147 mg/L June 2025; 145 September 2025; 158 March 2026): lethbridge.ca
- Health Canada, Guidelines for Canadian Drinking Water Quality: operational parameters (hardness forms scale in water heating appliances): canada.ca
- Parachute, Hot tap water (49°C at the tap; electric tanks at 60°C; gas and oil dial settings; mixing valves; thermometer check): parachute.ca
- City of Calgary, Service valves (where the main shut-off usually is): calgary.ca
- City of Calgary, High water consumption investigation checklist (meter test; food colouring test): calgary.ca
- City of Calgary, Sewage backups (backwater valves for below-grade fixtures; protective gear): calgary.ca
- City of Calgary, Protect your pipes (grease, wipes, hair; chemicals as household hazardous waste): calgary.ca
- City of Lethbridge, Composting and green carts (fats, oils and grease in the green cart; Hazardous Waste area at the Waste & Recycling Centre): lethbridge.ca
- EPCOR (Edmonton’s water utility), Backwater valve (how it works; inspecting and cleaning; don’t use water while it’s closed): epcor.com
- Health Canada, Use household chemicals safely (drain cleaners; corrosives; never mix; modified 2026-10-02): canada.ca
- Government of Alberta, Floods (electricity and water; ask your electricity supplier; electrician inspection): alberta.ca
- Technical Safety Authority of Saskatchewan, Electrical flood and water safety (water conducts electricity; disconnect only if safe, otherwise have the utility disconnect): tsask.ca