How much does it cost to drain and refill an inground pool with Ottawa city water?

Draining and refilling a standard residential inground pool in Ottawa costs approximately $180 to $350 in water and sewer charges alone, based on the City of Ottawa's combined rate of roughly $3.34 per cubic metre. A typical 16-by-32-foot pool with an average depth of 5 feet holds approximately 58,000 to 72,000 litres, and refilling that volume through your garden hose also requires $50 to $150 worth of startup chemicals to balance the fresh water — bringing the total cost of a complete drain-and-refill to roughly $230 to $500 before accounting for any professional labour.

Most Ottawa pool owners never need to completely drain and refill their pool. Partial water replacement through backwashing, splash-out, and rainfall dilution refreshes a significant percentage of the water volume each season naturally. However, there are legitimate situations where a full or near-full drain becomes necessary: total dissolved solids exceeding 3,000 ppm and causing persistent cloudiness, cyanuric acid (stabilizer) levels above 100 ppm that render chlorine ineffective, severe contamination events, structural repairs to the pool floor or walls, liner replacement, or replastering a concrete pool. If none of these conditions apply, a drain-and-refill is usually unnecessary and carries risks that outweigh the benefits.

The water cost calculation for Ottawa is straightforward. The City of Ottawa charges a combined water and wastewater rate per cubic metre on your regular water bill. To refill a 65,000-litre pool — a common size for a 16-by-32-foot pool in Ottawa neighbourhoods like Barrhaven, Riverside South, Kanata, and Stittsville — you would use 65 cubic metres of water at approximately $3.34 per cubic metre, totalling roughly $217. Add a 10 to 15 percent buffer for water used during the refilling process (hose setup, initial flushing, spillage), and your water bill increase will be approximately $240 to $250. This charge appears on your next regular water bill — the City of Ottawa does not offer pool-fill credits or reduced rates for seasonal pool filling, unlike some municipalities.

How long it takes to fill an Ottawa pool with a garden hose affects your planning more than your cost. A standard 5/8-inch garden hose at typical Ottawa municipal water pressure delivers approximately 30 to 50 litres per minute. At 40 litres per minute, filling a 65,000-litre pool takes approximately 27 hours of continuous running. Most homeowners leave the hose running overnight and through the next day, monitoring the water level periodically. Using two garden hoses from separate outdoor taps can cut the time roughly in half. Some Ottawa pool companies offer truck-delivered water at $200 to $400 per truckload of approximately 10,000 to 15,000 litres, which fills the pool faster but costs significantly more than municipal water — a full fill by truck would run $900 to $2,500, making it impractical for most homeowners except as a supplement to speed up the final stages.

The chemical startup cost after refilling with fresh Ottawa tap water is a significant portion of the total expense. Fresh city water has no cyanuric acid (chlorine stabilizer), minimal calcium hardness, and contains chloramines that must be addressed. A complete chemical startup for a freshly filled pool typically includes: granular chlorine or liquid chlorine for initial sanitization ($15 to $30), cyanuric acid to protect the chlorine from UV degradation ($20 to $40), sodium bicarbonate to raise total alkalinity to the 80 to 120 ppm range ($10 to $20), calcium chloride to raise hardness to an appropriate level for your pool surface ($15 to $30), and pH adjuster ($10 to $15). Budget $70 to $135 for chemicals if you do it yourself, or $150 to $250 if a pool company handles the startup including their service call fee.

Draining an inground pool in Ottawa carries structural risks that make professional guidance important. An empty or partially empty inground pool is vulnerable to hydrostatic pressure — groundwater pushing upward on the pool floor from below. Ottawa's heavy clay soil retains moisture well into summer, and the water table in many Ottawa neighbourhoods (particularly those near the Ottawa River, Rideau River, or in low-lying areas of Orleans, Gloucester, and Nepean) can be high enough to float an empty pool shell out of the ground. This is not an exaggeration — hydrostatic uplift has caused pool floors to crack, bow, or physically lift in Ottawa. Never drain your pool completely without first confirming the water table level and ensuring the hydrostatic relief valve (if your pool has one) is functional. If you are unsure, have a pool professional assess conditions before proceeding.

Vinyl liner pools require extra caution during draining. Most inground pools in Ottawa have vinyl liners, and exposing the liner to air — particularly in direct sunlight — causes it to shrink, dry out, and lose elasticity within hours. Once a vinyl liner shrinks, it cannot be stretched back into position and must be replaced at a cost of $3,000 to $6,000 including labour. If you must drain a vinyl liner pool for repairs, work as quickly as possible, keep the liner shaded and moist, and refill immediately after the repair is complete. Professional pool companies in Ottawa typically drain only to the minimum level required for the specific repair rather than emptying the pool entirely.

Is a Partial Drain a Better Option?

In many cases, draining and replacing 30 to 50 percent of the pool water achieves the same water quality improvement as a full drain at a fraction of the cost and risk. If your total dissolved solids are at 2,800 ppm and you want to get below 2,000 ppm, replacing half the water mathematically brings you to approximately 1,400 ppm — well within the acceptable range. A 50 percent water replacement on a 65,000-litre pool costs roughly $110 to $130 in water charges plus $30 to $50 in chemical adjustments, and it eliminates the structural risk of fully emptying the pool. For cyanuric acid reduction, the same math applies: if CYA is at 120 ppm and you replace 50 percent of the water, the resulting level drops to approximately 60 ppm, which is within the ideal range.

Considering a drain-and-refill or need advice on whether a partial water replacement would solve your issue? Ottawa Pool Installation connects homeowners with experienced local pool professionals who can assess your water quality and recommend the most cost-effective approach.