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Rehabilitating a well that has slowed
Deepening, redevelopment and repair for wells that no longer give what they used to.
A well that has lost yield is not automatically a well that needs replacing. Deepening, redevelopment and mechanical cleaning are all alterations under the Groundwater Protection Regulation, which means disinfection afterwards and an alteration report filed with the Province within 90 days. A well out of service for 5 years must be decommissioned.
Falling yield has three common explanations and only one of them is the formation running out. Screens and fractures clog, pumps get set at the wrong depth as water levels drop through the season, and casing fails. Establishing which one it is costs far less than drilling a second hole.
Rehabilitation is quoted on what the diagnosis finds, and the diagnosis is the cheap part. Redevelopment on an existing well sits well below the cost of drilling a new one; deepening sits between the two and carries the risk that the formation gives nothing more. That risk is the reason the camera and the yield test come first.
Deepening is not always the answer
Chasing depth works where a fracture system continues below the current bottom, and does nothing where it does not. In fractured bedrock — which is most of this region — water arrives through discrete fractures rather than evenly through the rock, so another 20 m can add nothing at all. The records for the aquifer are the first evidence: Aquifer 220 at Errington has a median depth of 60 m and dry holes logged past that, which tells you depth alone is not a strategy.
Redevelopment, and what it can recover
Mechanical redevelopment clears fines, scale and biological fouling from the screen or the fracture faces. It recovers yield that was lost to clogging rather than yield that was never there. On a sand-and-gravel well it is often the single highest-return intervention available; on a bedrock well it is more variable, and worth trying before deepening because it costs less and cannot make the well shallower.
When a well should be closed instead
The Groundwater Protection Regulation requires a well to be decommissioned once it has been out of service for 5 years. Decommissioning fills the well through its depth with sealant and backfill, with a closure plug at least 5 m long on a water supply well, and a decommissioning report is filed. An abandoned open well is a direct route from the surface into the aquifer, which is why the Regional District rebates the work at up to $500.
Rehabilitation work quoted
Redevelopment
Mechanical cleaning to recover yield lost to clogging, scale or biological fouling.
Deepening
Extending an existing well where the records support more water below the current bottom.
Decommissioning
Sealing a well that is out of service, with the closure plug and report the regulation requires.
How a slowing well gets diagnosed
- 1
History and records — the original well log and any alteration records pulled before anything is proposed.
- 2
Downhole inspection — camera survey to see casing condition, water entry and any obstruction.
- 3
Yield measurement — what the well actually gives now, against what it gave when drilled.
- 4
Options with numbers — redevelopment, deepening, or replacement, each with what it is likely to recover.
Why yield falls here
Yield here is modest to begin with, so a small loss is felt quickly. Aquifer 220 at Errington is rated low productivity with a median 3 US gallons a minute and a lower quartile of 1. Aquifer 162 at Cedar and Yellow Point sits near 2. Both are in long-term decline — Errington measured at about 0.32 m per year over one five-year window — and in June 2026 the Regional District of Nanaimo reported 16 of its 22 monitored aquifers below normal going into summer. A well that "stopped working in August" is often a well that was always marginal in August.
In practice
- Situation
- A Yellow Point property whose well ran clear all winter and went sandy and slow each August.
- Complication
- The camera showed the pump set close to the bottom, drawing sediment once the seasonal water level dropped.
- Resolution
- The pump was raised and the well redeveloped to clear the fines. No deepening, and the summer draw was cut to sit inside the measured yield.
People also ask
Will deepening a well always give more water?
No. In fractured bedrock water arrives through discrete fractures, so drilling past the current bottom only helps if another water-bearing fracture is down there. Records in the same aquifer include dry holes drilled well past the local median.
Does rehabilitating a well need to be reported?
Altering a well is reportable, and the report goes to the Province within 90 days. The well must also be disinfected after being altered, developed or rehabilitated.
When must an old well be closed?
Once it has been out of service for 5 years. Decommissioning seals the well through its full depth, with a closure plug at least 5 m long on a water supply well, and the work is reported.
Is there help with the cost of closing a well?
The Regional District of Nanaimo's Wellhead Upgrade Rebate covers up to $500 toward well closure, as part of up to $650 per wellhead. One rebate per wellhead.
A slowing well is diagnosed before it is quoted — a camera survey and a yield test, how the pump is set, what has to be reported and wells at Nanoose Bay.
Find out what is under the property.
Free site assessments across Electoral Areas A, B, E and F.