Blog · Waterloo
Testing a private well near Conestogo, St. Jacobs or Elmira: what to test, when, and where
Homes on private wells around Conestogo, St. Jacobs, Elmira and the rest of rural Woolwich are responsible for their own water quality. Testing is free for bacteria and simple to do, but it only helps if the sample is taken properly and on a schedule.
Last updated September 25, 2026 · Reviewed by the Waterloo Plumbing Co. team
How often the Region says to test
Region of Waterloo Public Health recommends that private well owners test:
- For bacteria three times a year: spring, summer and fall.
- For nitrates and fluoride once a year.
Ontario's guidance adds that you should test more often after unusual events: spring melt, flooding, work on the well or pump, or any change in the water's taste, colour or smell. In farm country around Woolwich, spring runoff and nearby manure spreading are both reasons to take an extra sample.
What the free test covers
Public Health Ontario analyzes well water for total coliforms and E. coli at no charge. That tells you whether surface water or waste is getting into the well. It does not test for chemicals, metals, pesticides or viruses.
The Region also runs nitrate and fluoride testing for private wells for a fee. Samples for those tests must come from a privately owned well in the Region, be collected in the official containers, and be taken before any treatment or filtration device. They are accepted on set days at designated sites.
Getting bottles and dropping them off
Sample bottles are available at Region of Waterloo offices and at library branches. Bacteria samples have set drop-off days: rural locations accept them on Tuesdays and urban locations Monday to Thursday. Check the Region's page for the current list before you fill a bottle, because the sample has a short life.
Results for bacteria are posted online, usually within a few business days, and you look them up with the barcode from your bottle. Questions about results go to the Region at 519-575-4400.
How to take a good sample
Most "bad" results that turn out fine on retest come from a poorly taken sample. Following Public Health Ontario's instructions:
- Use a cold tap inside the house, ideally one that is not a pull-out kitchen sprayer. Do not sample from an outside hose bib.
- Take off the aerator or any attachment.
- Disinfect the end of the spout with diluted bleach or rubbing alcohol.
- Run the cold water for two to three minutes.
- Fill the sterile bottle to the line without touching the inside of the cap or bottle.
- Keep it cool, not frozen, and get it to the drop-off quickly. Public Health Ontario says the lab must receive it within 48 hours of collection.
If you have a treatment system such as a UV unit or a softener, sample before it if you want to know the raw well water, and after it if you want to know whether the treatment is working. Label which one you did.
What the results mean
- No significant evidence of bacterial contamination: total coliforms 5 or fewer per 100 mL and no E. coli. Keep testing on schedule.
- Significant evidence of contamination: total coliforms above 5 per 100 mL and no E. coli. Surface water may be getting in. Inspect the well, consider shock chlorination, and retest.
- Unsafe to drink: any E. coli detected. This indicates contamination from human or animal waste. Stop drinking the water, use bottled water, and contact the Region's public health staff.
Shock chlorination and retesting
For a result showing significant coliforms, Ontario's guidance is to inspect the well and consider shock chlorination, a one-time high-strength chlorine treatment that can kill bacteria in the well, the pressure tank and the house plumbing. It can also help with iron bacteria that slow the flow. It is a fix for a one-off event, not a substitute for sealing the well if surface water is getting in. After any disinfection, wait until the chlorine has fully flushed out before sampling again, then retest to confirm the result. If contamination keeps coming back, a continuous treatment system such as UV, with filtration ahead of it, is the usual next step.
Finding the cause of a bad result
Ontario's rules make well owners responsible for keeping the well properly constructed, sealed and graded so surface water runs away from the casing. Common culprits:
- A cracked or loose well cap, or a cap buried below grade.
- Ground that slopes toward the casing, letting runoff pond at the well.
- A failing pitless adapter or casing seal.
- A recently serviced pump that was not disinfected afterwards.
Structural problems with the well itself belong to a licensed well contractor. Inside the house, the plumber behind this site handles the equipment side: pressure tanks, iron filters, UV disinfection units and softeners through water softener and filtration service. Ontario notes that every treatment system must be installed, operated and maintained as the manufacturer directs to stay effective.
Where this applies
Much of Elmira and St. Jacobs is on municipal water, but homes on the rural edges of those villages and across the countryside around Conestogo are often on wells. If you are unsure which you have, your water bill (or the absence of one) tells you. For treatment equipment costs, see the Waterloo plumbing cost guide, or ask the plumber to look at your system.