Inground Pool Closing: Complete Quebec Winterizing Guide
Time to read 17 min
Complete guide • Inground pools • Quebec
Prepare the water. Protect every circuit. Make spring easier.
Closing an inground pool involves more than simply adding a few products and installing a cover. In our climate, the main goal is to prevent water from freezing in the plumbing and equipment. A single improperly blown-out line, poorly drained heat pump, or incorrectly installed plug can lead to a major repair in the spring.
Each installation has its own layout, however: number of return lines, main drain, skimmer, salt system, water heater, heat pump, integrated spa, waterfall, automatic filler, pressure-side cleaner, or safety cover. The proper method must therefore follow the pool’s actual configuration and each manufacturer’s instructions. This guide presents a complete and safe sequence, but it does not replace a technical inspection when the plumbing is complex or unfamiliar.
Piscine Hippocampe assists homeowners in Delson, the South Shore, Montreal, and Montérégie with closing products, advice, and professional winterization. You can use this guide as a preparation checklist or entrust us with the closing so that each circuit is identified, drained, and protected.
Request a closing quote →Choose closing products →
Why an inground pool closing must be methodical
Remove water from the pipes, equipment, and low points exposed to freezing.
Protect the shell or vinyl liner by maintaining a water level suited to the type of cover.
Close the pool with clean, balanced water to reduce stains, scale, and algae.
Properly remove or isolate sensitive components: salt cell, pressure gauge, drain plugs, and accessories.
Document the position of the valves and components to simplify spring opening.
Install a cover compatible with the pool and the yard environment.
When should you close an inground pool in Quebec?
The best time is generally when the water remains around 12°C or lower, while still leaving enough time before a sustained freeze to complete the work properly. At this temperature, biological activity slows and the closing treatment remains more stable. Closing too early while the water is still warm increases the risk of finding green water in the spring; waiting for freezing temperatures can damage equipment before the pool is even closed.
Monitor the water temperature rather than just the calendar date. However, book your service several weeks in advance: the weather window is short, and professional closing appointments fill up quickly.
Should you close the pool yourself or hire a professional?
| Situation | DIY closing possible | Professional recommended |
|---|---|---|
| Plumbing | Simple, clearly identified circuits that have already been successfully closed. | Unknown layout, multiple branches, or valves that are difficult to understand. |
| Equipment | Standard pump and filter with the manuals available. | Heat pump, pool heater, spa, waterfall, solar system, UV/ozone system, or pressure washer. |
| Blowing | Suitable blower, exact plugs, and a well-mastered method. | Doubt about the main drain, watertightness, or the presence of residual water. |
| Risk tolerance | Ability to verify each step and accept the consequences. | Give priority to peace of mind and a documented closing. |
Simple rule: if you cannot explain where each pipe goes and how to confirm that it is empty, have a technician step in. A professional closing generally costs much less than repairing a cracked underground pipe.
The closing sequence to remember
| Phase | Finish before moving on |
|---|---|
| 1. Prepare | Identify circuits, investigate leaks and confirm the required water level. |
| 2. Clean and treat | Clean pool and filter, balance water and complete additions requiring filtration. |
| 3. Winterize | Lower water according to the plan, stop equipment, disconnect power and protect each circuit. |
| 4. Cover and monitor | Install the cover, store parts, record the final level and arrange checks. |
7 to 10 days before closing
Check whether the water level is dropping abnormally. A leak must be located before it is concealed by the winter cover.
Photograph the equipment, valves, and direction of flow. Label the pipes if they are not already labeled.
Note the makes and models of the pump, filter, salt cell, heat pump, and heater.
Confirm the water level required for your type of cover and pool finish.
Reserve the blower or closing service; confirm that the plugs and accessories match your installation.
Inspect the winter cover, springs, anchors, cables, and retaining devices before closing day
24 to 48 hours before
Vacuum, brush the walls, and remove leaves. Have the water tested at a store and correct the balance before adding the closing treatment. Clear, balanced water reduces the risk of deposits, corrosion, stains, and algae during the winter.
Clean the filter according to its type and the manufacturer’s instructions. A sand filter may require backwashing; a cartridge filter must be cleaned and dried if removed; a diatomaceous earth filter requires a procedure specific to its model. Do not add multiple concentrated products in the same place, and never mix chemicals together.
Closing water: what should be tested before buying a kit?
A closing kit does not balance the water by itself. Bring a recent sample, your pool volume and the products used. Green, cloudy or stained water needs a diagnosis first; covering it only postpones the problem.
| Parameter | Why it matters | What to do |
|---|---|---|
| pH and alkalinity | Balance affects water stability and material protection. | Have corrections established for your water and finish. |
| Sanitizer | Know available chlorine before final treatment. | Follow label doses and intervals rather than repeating shock treatments without testing. |
| Calcium, stabilizer and metals as needed | An algaecide does not automatically correct these. | Have results interpreted before adding more products. |
| Volume and cover type | These guide kit selection and capacity. | Confirm actual volume and whether the cover is solid or mesh. |
For a simple rectangular pool, length × width × average depth in metres × 1,000 estimates litres. Steps, benches and irregular shapes require adjustments. Prefer the volume provided with your pool instead of choosing a kit by pool length alone.
Choose and apply closing products
For products requiring circulation, finish this step before final shutdown and equipment drainage. Treatment depends on testing, volume, sanitizer and cover type. Follow each label’s order, quantities and timing.
The Premium Dazzle kits shown here contain Ultra Shock and Algae Clear 60; the Pristiva saltwater kits contain Premium Shock and Primer. Formats for up to 40,000 L and 80,000 L are not interchangeable without checking directions. Ask whether a mesh cover calls for an additional program.
Add products separately. Avoid concentrates settling on the liner and never mix products in one container. More product does not mean more protection. A kit treats water; it does not winterize water-filled pipes or equipment.
Dazzle or Pristiva: choose for your pool
Select the treatment system first, then capacity. Check cover compatibility as well; unbalanced or heavily contaminated water may require additional preparation.
Dazzle Premium — up to 40,000 L
Ultra Shock and Algae Clear 60. Particularly suited to solid winter covers according to the product information.
View Dazzle 40,000 L kit →
Dazzle Premium — up to 80,000 L
The larger-capacity format. Check each container’s directions against your actual volume.
View Dazzle 80,000 L kit →
Pristiva saltwater — up to 40,000 L
Premium Shock and Primer to prepare saltwater pool water for closing.
View Pristiva 40,000 L kit →
Pristiva saltwater — up to 80,000 L
A format for larger saltwater pools, selected with advice for your installation.
View Pristiva 80,000 L kit →Equipment generally required
| Category | Examples | Checkpoint |
|---|---|---|
| Blowing | Pool blower, hoses, and adapters. | Sufficient flow and completely watertight connections. |
| Sealing | Threaded or expandable plugs and return plugs. | Exact dimensions for each opening. |
| Skimmer | Gizzmo or foam kit. | Compatibility with the skimmer and sufficient expansion space. |
| Protection | Non-toxic antifreeze designed for pools and spas. | Use only as directed on the label; never use automotive antifreeze. |
| Maintenance | Closing kit, filter cleaner, and brush. | Products suitable for a chlorine or saltwater system. |
| Safety | Glasses, gloves, tools, and containers clearly labeled. | Power turned off and filter pressure at zero. |
| Cover | Opaque cover, locking cover, or Safety Cover. | Water level and anchoring compatible with the system used. |
Before you begin: three safety rules
Electricity and pressure: Turn off the power at the circuit breaker before disconnecting or draining an appliance. Always stop the pump before moving the handle on a multiport valve. Open the filter air-relief valve and wait until the pressure gauge reads 0 before performing any maintenance.
- Consult the manual for each piece of equipment. The location of drain plugs and the winterization procedure vary by model.
- Never work on a pressurized circuit, and do not power equipment back on until the plumbing has been reassembled for opening.
- Wear the protective equipment specified on the labels. Add each product separately, with the required circulation, and store it in its original container.
How to close an inground pool: the steps
Determine the final water level
There is no single height that applies to all pools. The level depends on the vinyl liner or finish, the position of the return fittings and skimmer, the type of plugs, and the winter cover. A floating opaque cover, a locking cover, and a Safety Cover are not managed exactly the same way.
Follow the pool and cover manufacturer’s instructions. Never completely drain a vinyl-liner pool: the weight of the water helps keep the liner in place and supports the structure. With a safety cover, the water level must also remain high enough to support the cover under a significant load, according to its instructions.
Remove accessories and prepare the pool
- Remove ladders, removable rails, toys and the robotic cleaner according to their manuals.
- Clean and dry the solar cover before storage.
- Clean and reinstall baskets for final filtration; remove for storage only after final shutdown if prescribed.
- Complete brushing and filtration before continuing.
- Lower water to the approved level without running the pump dry.
If water falls below the skimmer, do not allow the pump to draw air. Confirm a drainage method suited to available intakes and follow local discharge rules, particularly for saltwater.
Turn off the power and release the pressure
Stop the pump, switch off the equipment breakers, and prevent accidental re-energization. Open the filter air-relief valve until the pressure gauge reads 0. Then close or position the valves according to the circuit that will be blown out. Take a photo of each configuration to make reopening easier.
Blow out and isolate lines according to the actual plumbing plan
Skimmers, returns, suction ports, main drains and accessories may form separate branches. Establish valve order and connection points before blowing. The aim is to clear freeze-exposed sections and prevent water returning as required by the circuit’s design.
Use only a compatible high-volume, low-pressure pool blower following connected equipment limits. Never pressurize a filter tank or block every blower discharge path. A high-pressure workshop compressor is not a substitute.
Main drains need particular attention. Protection differs when the drain connects through the skimmer, a dedicated valve or another arrangement. An air lock is appropriate only when the layout supports it and retention can be verified. Have an unknown drain configuration identified and winterized professionally.
Caution: A shop vacuum can work on some simple installations, but it does not always produce the flow required for a long pipe, a low point, or a main drain. The absence of bubbles does not automatically prove that a pipe is empty. If in doubt, stop and have the system checked.
Use antifreeze as additional protection
A non-toxic antifreeze designed for pools and spas may be added to certain pipes after blowing them out, depending on the label and the configuration. It never replaces complete draining and blowing. Do not use automotive antifreeze: its formulation is not intended for pool water and may pose a hazard.
The volume and addition point depend on the length, diameter, and slope of the pipe. Do not pour a product at random into a system whose layout you do not know.
Protect the skimmer
Once the skimmer line has been blown out and plugged, install a device designed to absorb or accommodate ice expansion, such as a Gizzmo or a compatible foam assembly. The goal is to provide expansion space in the skimmer; this device does not eliminate the need to properly protect the line.
Winterizing the pump, filter, and equipment
Draining the pump
With the power off and the pressure released, remove all drain plugs identified in the pump manual. Let the housing and basket drain completely. Clean the basket, lubricate the seal only with a compatible product if the manufacturer recommends it, and store the plugs in the basket so you can find them in the spring.
Protect the motor from the elements without wrapping it airtight in plastic, which would trap moisture. The thermal-protection or freeze-protection mode of a variable-speed pump does not replace winterization when the pool is closed.
Winterizing the filter
| Type | General preparation | Things to remember |
|---|---|---|
| Sand | Complete prescribed backwashing and rinsing before final shutdown. Stop the pump before each change of the valve position. | Empty the tank and set the valve to WINTERIZE if specified by the manufacturer. |
| Cartridge | Open the filter, remove the cartridge, and clean it according to the manufacturer’s instructions. | Let it dry before storing it, then inspect the folds and seals. |
| Diatomaceous earth | Backwash, open the filter, and clean the grids according to the model. | Handle and dispose of the earth in accordance with local regulations, then carefully inspect the grids. |
Important: remove the bottom drain plug and let the filter drain completely. Remove or protect the pressure gauge and sensitive accessories if the manufacturer recommends it. A multiport valve must never be moved while the pump is running.
Closing a saltwater pool
Cold water may reduce or stop chlorine production depending on the model. Keep testing before closing and use a compatible sanitizer as needed. After switching off the power, remove the cell if the manual requires it, inspect it, rinse light deposits with a hose, and store it in a dry, frost-free place.
Do not automatically perform an acid wash every fall. Excessive chemical cleaning can damage the plate coating. Use it only when stubborn scale is present and according to the manufacturer’s method. A dummy cell can be installed on some systems to close the circuit during winter.
Winterize the heat pump or heater
Turn off the circuit breaker, isolate the unit from the circuit, and drain all water from the connections, heat exchanger, and low points according to the manual. A small amount of trapped water may be enough to crack a heat exchanger. On some heat pumps, the inlet and outlet connections must be disconnected for drainage, then left in the prescribed winter configuration to prevent refilling.
Gently clean a heat pump's coil with a low-pressure hose if necessary; a high-pressure jet can bend the fins. Install a cover only if it is designed for the model and recommended by the manufacturer. Gas heaters also require special attention to the power supply and ventilation: have this part handled by a qualified technician if you are unsure of the procedure.
Treat special circuits and accessories
- Integrated spa: blow out the jets, suction lines, air lines, and overflow separately.
- Waterfall or water blade: drain the dedicated pump, reservoir, and each line.
- Pressure cleaner: protect the line and booster pump.
- Automatic filling: shut off the water supply and drain the line exposed to freezing temperatures.
- Solar heating: follow the manual for draining the panels, collectors, and valves.
- UV, ozone, or dosing systems: remove or protect fragile components according to the manufacturer's instructions.
- Lights: turn off the power and follow the procedure specific to the model; never turn on a light fixture outside the water.
These options are the main reason a generic procedure can fail. Make a complete list of the branches before starting; every circuit containing water must be drained, blown out, isolated, or protected according to its design.
MOOV owners can also read our MiniSalt guide and dummy replacement fitting section. The fitting must match the system; it does not generate chlorine or replace winter drainage.
MOOV MTS50 winter cover
A model-specific cover used only after winterization. Never cover an operating unit.
Check the MTS50 cover →Shopping checklist: accessories to confirm
Dazzle pool and spa antifreeze
Additional protection for label-approved applications. Quantity depends on the line, not just pool volume.
View antifreeze →
Super Gizzmo
For compatible inground skimmers. Confirm depth and threads; it does not replace line protection.
View Super Gizzmo →
Skimmer foam — inground version
The link preselects the inground variant. Confirm compatibility with your skimmer before purchasing.
View inground version →See winter plugs and closing accessories as needed. Confirm plug size and shape from the existing part or photos and measurements.
Install and monitor the winter cover
| Cover type | Principle | Essential check |
|---|---|---|
| Floating opaque cover | Rests on the water and is held in place according to the system used. | Check the management of the water, cable, or weights according to the manufacturer's instructions. |
| Locking cover | Fits into a track installed around the pool. | Check the water level, tension, and complete locking of the cover. |
| Safety Cover | Is stretched over the pool using springs and anchors. | Check the support water level, tension, anchors, and obstacles around the pool. |
Important: Clean the cover before installation and replace any damaged components. A safety cover is not a play area and does not replace a compliant fence or supervision. After installation, make sure the cover does not rub against any corner, rock, or metal element.
A winter cover or leaf net is not automatically a safety cover. Confirm the manufacturer’s stated purpose and installation requirements. Safety-cover springs, anchors and water support work together; do not copy another pool’s water level.
Understand custom safety covers →Explore winter covers →Special situations: when should the installation be checked?
| Situation | What to do |
|---|---|
| Pool loses water before closing | Find the cause before covering. Winter losses may compromise cover support. |
| Equipment sits below pool level | Water pressure may refill a drained unit. Confirm isolation points and valve tightness. |
| Main drain connects through the skimmer | Identify the configuration; it may require a different method from an independent air-lock line. |
| Freezing weather arrives before your appointment | Contact service promptly. Timers and freeze modes do not guarantee protection through prolonged freezing or a power failure. |
| Part of the installation is already frozen | Do not force valves or try restarting equipment. Have it assessed first. |
| A branch cannot be identified | Do not assume it is protected; have its route and winterizing method checked. |
Concrete, fiberglass and vinyl-liner inground pools should not be fully drained for routine closing. Significant drainage requires professional assessment of the basin, ground conditions and water surrounding the structure.
Before the appointment: prepare for an effective closing
- Clear access to the yard, equipment area and pool equipment.
- Send photos, water volume and equipment model numbers.
- Report leaks, recent repairs and rarely used circuits.
- Gather the cover, attachments, plugs and stored accessories.
- Confirm what is included: cleaning, products, line winterization, heating, salt system and cover installation.
- Discuss drainage arrangements and access requirements before the visit.
Afterwards, keep photos, winter valve positions, removed-part records and monitoring recommendations. These also help whoever performs spring opening.
What should you check after closing?
Inspect the cover, anchors, and fasteners after strong winds and heavy rain or snow.
Carefully remove branches without using sharp tools or walking on the cover.
Monitor the water level according to the type of cover; an unusually low level may indicate a leak.
Make sure the circuit breakers for the closed equipment remain switched off.
Keep the removed components, plugs, and closing notes together in a labeled container.
Plan the opening early enough in spring, especially with a mesh cover that lets some light through.
Rain, snow and thaws: distinguish the two water levels
Water inside the pool supports certain covers and must remain in the specified range. Water on a solid winter cover is managed according to that cover’s instructions. Do not assume the same procedure applies to both. Incorrect cover-pump use or a damaged cover may contribute to pool water loss.
Do not break ice with tools or walk on the cover. After a thaw or heavy rain, visually check attachments and level if safe. If water drops unusually or the cover changes shape, seek advice before pumping more.
Closing does not eliminate spring monitoring
A long warm period can encourage algae, especially beneath mesh. Plan an early opening and establish suitable treatment at the first thaw. Do not restart filtration before removing winter plugs and reassembling equipment according to the opening procedure.
The most common closing mistakes
| Mistake | Possible consequence | Best practice |
|---|---|---|
| Close too early | Green or cloudy water in spring. | Wait until the water is around 12 °C, without risking freezing. |
| Ignore a leak | Water level too low, putting the liner or structure under strain. | Diagnose and fix the leak before covering. |
| Use a universal water level | Incompatibility with the liner or water returns. | Follow the instructions specific to the pool and cover. |
| Blowing out lines without a plan | Forgotten line or lost air lock. | Identify, treat, and label each circuit. |
| Relying solely on antifreeze | Residual water and risk of freezing. | Drain and blow out the lines before adding any additional protection. |
| Forgetting a pump or filter plug | Cracked housing or tank. | Remove all drain plugs indicated in the manual. |
| Cleaning the salt cell with acid without reason | Premature wear of the cell coating. | Rinse with water first and treat only stubborn scale. |
| Wrapping the motor airtight | Condensation buildup and corrosion. | Protect the motor from the elements while allowing good ventilation. |
| Moving the valve while the pump is running | Possible damage to the valve or system. | Always stop the pump before handling anything. |
Frequently asked questions about closing an inground pool
At what temperature should an inground pool be closed?
Generally aim for water that remains around 12°C or lower, before a period of sustained freezing. Water temperature is more useful than a fixed date.
Can an inground pool be closed too early?
Yes. In water that is still warm, algae and microorganisms remain active. Even with a closing kit, the risk of green water in spring increases.
How far should the water level be lowered?
The level depends on the finish, returns, plugs, and type of cover. There is no universal measurement; follow the manufacturer’s instructions and never completely drain a vinyl-liner pool.
Is antifreeze mandatory?
Not in every system. It provides additional protection when recommended, but does not replace a complete blowout. Use only a non-toxic antifreeze intended for pools and spas.
Should the salt cell be removed?
Several manufacturers recommend removing it, rinsing it, and storing it in a dry, frost-free place. Check your model’s manual and always turn off the power before disconnecting it.
Which cover should you choose for an inground pool?
The choice depends on the shape of the pool, the deck, the required water level, the budget, and the protection desired. A custom Safety Cover provides taut coverage adapted to the pool’s particular features.
Is a closing kit enough to protect the pool?
No. It supports water preparation. Plumbing, skimmer, pump, filter and heating require separate mechanical winterization.
Should every drain plug be reinstalled after draining?
It depends on the equipment. Some manufacturers require drainage to remain open through winter. Follow the manual, protect openings as specified and label stored parts.
Can I use a workshop compressor?
Do not connect a high-pressure compressor to a filter or closed circuit. Winterization requires compatible high-volume, low-pressure equipment. If you cannot control the connection and air discharge correctly, hire a professional.
Which kit should I choose for more than 40,000 L?
Check the 80,000 L format’s capacity and instructions, then confirm suitability for the volume, water system and cover. Do not assume every product should simply be doubled.
Inground pool closing on Montreal’s South Shore
Piscine Hippocampe in Delson can help with supplies and assess professional closing based on your installation and service area. Provide volume, city, equipment and pool features for a suitable quote.
Request my closing quote →Continue preparing
Manufacturer references : Latham, Pentair, Meyco, Dazzle / Pristiva. Your pool, cover and equipment manuals remain the reference for your installation.
