Ontario's Plain-English Guide to Custom Home Buildingπ 705-533-1633 | βοΈ 1-866-868-6606 | βοΈ info@icfhome.ca
Well Yield and Flow Tests in Ontario: Gallons per Minute, Storage in the Casing, the Test at Drilling and at Purchase, and the Fixes for a Low-Yield Well
Plumbing & Water
Well Yield: Not How Much Water Is Down There, but How Fast It Comes Back
People ask how much water a well has, as if it were a tank. It is not. A well is a hole that fills from the ground around it at its own speed, and that speed, the yield, is what decides whether two showers and a load of laundry can happen on the same morning. A good well and a poor well can look identical from the lawn. The only way to know is to test it and write the result down.
The numbers
about 1.5US gallons stored per foot of water in a 6-inch casing
1 gpmis 1,440 gallons a day, if storage covers the peaks
from $2,000a cistern for a low-yield well
quoted per jobthe yield or flow test itself
| Item | Cost | Note |
|---|---|---|
| Yield or flow test at drilling | quoted per job | ask the driller to include it and record it |
| Well inspection plus water test, at purchase | $300 to $600 | a Canadian cost guide |
| Cistern for a low-yield well | upwards of $2,000 | a well-locating company |
| Drilling deeper, per foot | $45 to $120 | $80 default; the driller sets the deepening price |
| Hydrofracturing | quoted per job | a question for the driller |
| A dry hole | paid for anyway | about $12,000 lost on a 160 ft hole (Cottage Life) |
October 2026, before HST. The full drilling price by depth is on the well drilling cost page; we do not repeat it here.
Why Ontario prices are all over the map: the well companies and guides we checked quoted very different prices for drilling, which is what most low-yield fixes come down to. An Ottawa-area well company, a Canadian cost guide, Cottage Life and a well-locating company ranged from $45 to $120 a foot. A national marketplace printed both $10,000 to $15,000 and $15,000 to $30,000 for an Ontario well on the same page. Rock, depth, casing and the driller’s minimum explain most of it (the driller we use around Georgian Bay charges $15,000 for any well up to 75 ft (pump not included)). Budget $80 a foot or the minimum, whichever is more, and get two or three quotes on the same written scope, with the yield test written into it.
Gallons per Minute Is Only Half the Story
Yield is the rate the well refills, in gallons per minute. A house does not use water at a steady rate, though. It uses nothing all night and then everything at 7 a.m. What carries you through the morning rush is storage: the water standing in the casing above the pump, plus what is in the pressure tank.
The casing is a bigger tank than people think. A 6-inch casing holds about 1.47 US gallons for every foot of water standing in it. Say the water stands 140 ft deep above the pump: 140 x 1.47 is about 206 gallons waiting for you. A well that refills at only 1 gpm still brings back 60 gallons an hour, or 1,440 gallons over a day. That well can serve a careful house. It cannot serve a house that runs the lawn sprinkler, fills a hot tub and does four loads of laundry on Saturday.
So the questions are always two: how fast does it refill, and how much is stored when you start. A strong well with little water standing in it can run short, and a slow well with a deep column of water can do fine.
The Test at Drilling
When a new well is drilled, the driller pumps it to see what it gives and how the water level behaves. Ontario has requirements and best practices for the yield test on a new supply well. What you want, as the owner, is the result in writing, on the well record, which the contractor has to give you within 14 days and file with the ministry within 30 days.
- Put the yield test in the drilling quote. It is easy to agree to at the start and awkward to ask for after the rig leaves.
- Ask for the pumping rate, how long it ran, the static water level before, the level while pumping, and how fast it recovered. Those five numbers tell a future pump installer most of what they need.
- Get the depth to the pump intake and the pump size written down when the pump goes in.
- Keep the well record with the house papers. When you sell, the buyer will want to see it.
Before you drill, look up the neighbouring wells on Ontario’s well records map. Search by address and click a well to open its record. It will not promise you anything, but if every well on your road went 200 ft into rock, plan for 200 ft. More on that is on the checking for water on a lot page.
The Flow Test When You Buy
Buying a house with a well, you are buying the well too, and the seller is not likely to mention that it runs dry in August. Ask for the well record. If there is none, a missing record can be requested from the ministry, and the neighbours’ records on the map give you some idea.
Then make the offer conditional on a well inspection with a flow test and a water test. A Canadian cost guide puts an inspection plus water test at $300 to $600. We found no published price for the flow test on its own, so get it quoted, and make sure the scope says how long the well will be pumped and at what rate. A ten-minute run of the kitchen tap is not a flow test, and neither is the seller saying the pressure is great.
Fixes for a Low-Yield Well
A low-yield well is not always a failed well. It is a well that needs the house to be patient. The fixes, cheapest first:
- Use it more evenly. Laundry on weekday evenings, not all on Saturday. Not glamorous, free.
- Add storage. A storage tank or cistern lets the well trickle in all day and night, and a second pump pushes water from the cistern to the house. A well-locating company puts a cistern for a low-yield well upwards of $2,000; the second pump is priced on the well pump replacement page.
- Go deeper. A deeper well adds water standing in the casing and may reach more water-bearing rock. If the driller charged the $80 default for another 60 ft, 60 x $80 is $4,800, and there is no promise of more water.
- Ask the driller about hydrofracturing. It is a technique for opening up the rock around an existing drilled well. We found no published Ontario price; it is a question for the driller, quoted per job.
- Drill a new well somewhere else on the lot, and plug and seal the old one. The rules for that are on the well regulations page.
Remember the dry hole: you pay for the drilling whether it finds water or not. Cottage Life’s author lost about $12,000 on a 160 ft dry hole, which works out to $75 a foot for nothing but a story. Going deeper on a well that already gives some water is a gamble with better odds, but it is still a gamble.
Do not let anyone sell you a bigger pump for a low-yield well. A bigger pump just empties it faster. The water pressure problems page helps sort a yield problem from a tank, switch or filter problem, because a plugged sediment filter can look a lot like a well running dry.
A buried cistern means a hole in the yard and a line to the house. That is site work, and on Georgian Bay lots GeorgianBaySiteworks.ca handles that side of it. On our own builds the wells are drilled by licensed well contractors we hire.
Questions people ask
What is a good yield for a house well in Ontario?
It depends on the yield and on how much water is stored in the casing and tanks. A well that refills at 1 gpm still gives 1,440 gallons a day if storage covers the morning peak. Ask the driller what the house you are building needs, and get the test result on the well record.
How much does a well flow test cost?
We found no published Ontario price for a flow test on its own. A Canadian cost guide puts a well inspection plus water test at $300 to $600. Get the flow test quoted with the length and rate of the pumping written in.
Can a low-yield well be fixed?
Often. A storage tank or cistern, upwards of $2,000, lets a slow well keep up. Drilling deeper or hydrofracturing may add water, quoted per job by the driller. Sometimes a new well elsewhere on the lot is the answer.
Where do I find the yield of my existing well?
On the well record, if one was filed. Search Ontario’s well records map by address and click your well, or request a missing record from the ministry.
Price the whole water system
The rural water system cost calculator puts the well depth, the pump and tank, the trench and line, the water test and the treatment on one sheet, with low, middle and high totals. If you have drilling or cistern quotes, the $99 review reads up to three of them and tells you whether the yield test is in them.
Sources and further reading
- Water supply wells: the yield test: Ontario requirements and best practices for testing how much water a new well will give.
- Ontario well records: the well records map and data: search by address and open the records of the wells around you.
- Wells on your property: Ontario: the owner is responsible for the well, testing at least three times a year, and when a well record is required.
