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Plumbing and Water in Ontario (2026): New-House Plumbing, Wells and Rural Water, Water Testing and Treatment, Drains and Flood Protection, Permits and Hiring a Plumber
Trade GuidesPlumbing & Water
Plumbing and Water: Water Always Wins, So Plan Where It Goes
New-house plumbing, wells, water treatment, flood protection, permits and hiring, from a builder with more than 300 houses behind him.
Plumbing is the trade you notice only when it fails, and when it fails it fails wet. A drain forgotten under a slab is a jackhammer, and an untested well is a gamble with your kids' stomachs. This section is what it costs, what the code and the health unit want, and who is allowed to do any of it.
What this section covers, and what lives elsewhere
Five parts: plumbing a new house, including ICF walls and basement bathrooms; wells and rural water; water testing and treatment, where the free test comes before the equipment; drains, sewers and flood protection; and permits and hiring, which costs the least and saves the most.
Two big subjects live elsewhere on purpose. Septic systems have their own pages: septic systems in Ontario, septic system cost, the septic system calculator and buying a house with septic, and SepticReplacement.ca goes deeper on replacing one. Hot water lives in the Heating, Cooling & Ventilation section, starting at the home heating guide, with renting or buying a water heater and tankless sizing.
It does not teach gas work, work inside a well casing or anything on a relief valve. It tells you what the job should include and what to ask.
$1,300per fixture, new house rough-in plus trim, labour (defaults $1,000 + $300)
$80per foot, drilled well including casing in most quotes ($45 to $120)
$2,500water softener installed ($1,200 to $4,500)
$2,800backwater valve retrofit, GTA typical ($2,000 to $4,500)
Ontario, installed, before HST, October 2026 prices. A house with 12 fixtures at the defaults is 12 x $1,000 = $12,000 of rough-in plus 12 x $300 = $3,600 of trim, about $15,600, our estimate, before the water heater, the permit, the underground and the fixtures themselves.
Why Ontario prices are all over the map: the contractors and published price guides we checked for this section quoted very different prices for what sounds like the same job. New-house rough-in ran $800 to $1,200 a fixture from a Toronto plumber, about $950 from an Ottawa plumber and $800 to $1,800 from a Halton plumber, which on 12 fixtures is anywhere from $9,600 to $21,600 for the rough-in alone. Some quotes include the trim, the fixtures, the water service and the water heater, and some include none of them. Budget $1,300 a fixture for rough-in and trim, price the fixtures as an allowance, and get two or three quotes on the same written scope.
Start here
New-house plumbing
What the plumbing costs per fixture, plumbing an ICF house, adding a bathroom, PEX against copper, pressure problems and cottage plumbing.
Wells and rural water
Well pumps and tanks, drilled against dug, yield and the flow test, lake intakes, and the well rules in plain words.
Water testing and treatment
The free bacteria test, lab chemistry, softeners, iron filters, UV and reverse osmosis, and the order they go in.
Drains, sewers and flood protection
Sump pumps, backwater valves and the city subsidies, sewer laterals, and old pipe that insurers ask about.
Permits, hiring and inspections
What needs a plumbing permit, checking a licensed plumber, comparing quotes, and the checklist for each inspection.
The calculators
Free, on the same October 2026 prices the pages use. A budget and a good question, not a quote.
Rural water system cost calculator
The whole system on one sheet: the drilled well by depth and price per foot, the pump and tank, the trench and line, the water test and the treatment, with low, middle and high totals.
Water treatment selector
Enter your lab results, bacteria first, and get the treatment in the usual order with what each step costs installed and per year. It will not recommend anything without a recent bacteria test.
Water heater rent or buy calculator
Your monthly rental against buying a tank, a heat pump water heater or a tankless, over the years you will stay, with the buyout and the upkeep.
Plumbing cost estimator
Already on the site: new-construction plumbing per fixture and per square foot, municipal against well and septic.
Also on the site: well drilling cost, the generator and battery sizing calculator and every calculator.
Who does what
Most trouble starts when one of these assumes another was handling it.
| Who | What they do | What they do not do |
|---|---|---|
| Licensed plumber | A compulsory trade (306A): holds a Certificate of Qualification or provisional certificate, or is a registered apprentice under one. Check the Skilled Trades Ontario public register. | Gas work, unless the company is also a registered gas contractor. Well work without a well licence. |
| Licensed well contractor | Drills, repairs and plugs wells under Reg. 903 with licensed well technicians, and gives you the well record within 14 days. | Is not automatically a plumber. The house side is the plumber's job, so ask who does what. |
| Registered gas contractor | TSSA-regulated work: gas piping and gas water heaters, by a certified gas technician. | Never a homeowner job. |
| The municipal building department | Issues the plumbing permit and inspects the underground, the rough-in and the final. | Does not design or quote. It will not pass a drain it cannot see. |
| The public health unit | Hands out the free bacteria test bottles and explains a bad result. | Does not test for chemicals; that is a private lab. |
| The homeowner | Is responsible for the well. Picks the fixtures, keeps the well record and permit papers. | Cannot hire an unlicensed person to do plumbing. |
The rules that save the most money
- Hire a licensed plumber and check the register before the deposit. A handyman with a pipe wrench is not a plumber in Ontario. How to hire a plumber.
- A permit to add, move or alter plumbing, and nothing gets covered before inspection. Not the trench, not the slab, not the drywall. Plumbing permits.
- Gas is TSSA work. Gas piping and gas water heaters are done by a registered gas contractor with a certified gas technician. Never by you, never by a friend.
- Under-slab plumbing is inspected and protected before the pour. Plumbing an ICF house.
- Test the well at least three times a year. The bacteria test is free. If E. coli shows up, do not drink the water (boil it or use another source) until the well is fixed and two clean tests in a row come back. Well water testing.
- Sump and weeping tile water never goes into the sanitary sewer, a floor drain or a laundry tub. The code and the sewer bylaw both say no. Sumps and backwater valves.
- Never climb into a dug well or a well pit. Gases and low oxygen kill people every year.
- Two or three quotes on the same written scope. The comparison grid.
What we do on our own houses
I build ICF houses with hydronic radiant floors. The exterior walls are foam forms filled with concrete, so anything that passes through them, from the well line and septic outlet to the hose bibs, vents and sump discharge, needs a sleeve set in the form before the pour. We walk the house with the trades before the pour with a list of every penetration. Forget one and it is a core drill, an allowance of $150 to $400 a hole plus the patch and the seal.
The radiant tubing is tied down in the basement before the slab is poured, so the drains, the sump pit and any future bathroom rough-in have to be placed, inspected and protected first. Our showhome in Tiny Township costs about $100 a month to heat in the coldest part of winter, and none of that helps if somebody forgot the floor drain. If you want to see how we build, ICFhome.ca is the building side.
Rural Simcoe County and Georgian Bay houses run on drilled wells and septic. When the power goes out, the water goes too; read rural power outage planning before the first ice storm.
Have quotes in hand? Let a builder read them first
For $99 I read up to three plumbing, well or water treatment quotes, or one quote plus your water test report, and put them on one grid: fixtures, rough-in and trim, the water heater, the underground and service or well line, the pump and tank, the treatment and its order, the permit and the warranty. You get a written answer on what each one left out, in dollars, and which one I would sign.
There is no contractor network behind it and no referral fee on who you hire. We are a builder, not a plumbing contractor or a well contractor: on our own builds and renovations in Simcoe, Muskoka and Georgian Bay the plumbing is done by licensed plumbers we hire and the wells are drilled by licensed well contractors. Outside that area I will tell you honestly whether I know anyone.
Questions people ask
Can I do my own plumbing in Ontario?
In most Ontario municipalities you can do the plumbing in a house you own and live in, but you still need the permit and the inspections, and you cannot hire an unlicensed person to do it for you. Check with your building department first. Gas is a different matter entirely: that is TSSA-regulated work for a registered gas contractor, never a homeowner job.
How much does the plumbing in a new house cost?
Rough-in runs about $800 to $1,200 a fixture and trim another $250 to $350 a fixture in labour, so a 12-fixture house is about $12,600 to $18,600 by our estimate, before the water heater, the permit, the underground, the water service or well line, and the fixtures. What plumbing a new house costs and the plumbing cost estimator do the arithmetic.
How do I get my well water tested?
Pick up a free sample bottle from your public health unit or a pickup point, follow the instructions on it, and get it to the lab within 48 hours. Public Health Ontario tests for total coliforms and E. coli only; chemistry goes to a licensed private lab for a fee. Testing and treatment.
Do I need a backwater valve?
On a new house the code requires one where fixtures sit below the street or below the upstream sanitary manhole cover, and it has to be a normally open type serving one dwelling unit. On an older city house it is the best defence against a sewer backup, and several cities pay part, if you qualify. Drains, sewers and flood protection.
Price the water system before anyone quotes it
The rural water system cost calculator puts the well, the pump and tank, the line to the house, the test and the treatment on one sheet at October 2026 prices, so you know what a fair quote looks like. When quotes arrive, send up to three to the $99 review.
Sources and further reading
- The 2024 Ontario Building Code: Ontario on the 2024 Code: in force January 1, 2025, the grace period to March 31, 2025, and the harmonization with the national codes.
- Skilled Trades Ontario: Plumber: the compulsory plumber trade, the 9,000-hour apprenticeship and the Certificate of Qualification that must be renewed to be valid.
- Public Health Ontario: well water testing: the bacteria test, the 48-hour rule for samples, and how to read the result.
