Pool opening: step-by-step checklist
The correct order for getting a pool ready after winter, with realistic timing for each step and the mistakes that turn a one-day job into a week.
Before you start: timing matters
The rule is simple: open before the water goes above 15°C (59°F). Below that temperature algae barely grow and opening is routine; above it, every week of delay means more shock product, more filtration hours and water that never quite clears up.
The full checklist
Day 1 · Clean the obvious
- Remove the winter cover, clean it and store it dry
- Skim leaves from the surface and floor
- Empty skimmer baskets and the pre-filter
Day 1 · Level and startup
- Refill water up to the middle of the skimmer
- Check gaskets and seals
- Start the filtration system on continuous mode
Day 1 · First readings
- Measure alkalinity, pH, chlorine and, if you've used tablets for years, cyanuric acid
- Adjust in this order: alkalinity, pH, then chlorine
Day 2 · Shock and brush
- Shock chlorination once pH is at 7.2
- Brush walls, waterline and steps
- Vacuum the floor
Day 2-3 · Filter and clean the filter
- Continuous filtration for 24-48 hours
- Backwash when the pressure gauge rises 0.3-0.5 bar
- Repeat until the water is clear
Closing · Technical check and record
- Check lighting, salt chlorinator, dosing pumps and timer
- Log the final readings to start the season with a baseline
Managing dozens of openings
For a professional, April isn't a single day of work: it's forty or a hundred openings in three weeks, each with a different starting condition. What makes the difference is organizing the campaign by zone and keeping a record of the condition each pool was found in.
Group by area. One morning per town or development cuts more dead time between pools than any other improvement.
Photograph the initial condition. It's the best defense when a customer disputes the cost of a green water recovery.
Log the first day's readings. Everything you measure at opening becomes the baseline you'll compare the rest of the season against. The full maintenance guide covers the frequencies for the rest of the year.
Keep reading: How to get pool maintenance clients · How to price pool maintenance service
Frequently asked questions
When should you open the pool?+
When the water consistently rises above 15°C (59°F), usually between late March and early May depending on the region. Opening late is the most costly mistake: above 15°C, algae growth accelerates and recovering the water requires much more product.
How long does it take to get a pool ready?+
With a proper winterizing job, 2 to 4 hours of work spread over a couple of days, plus 24-48 hours of continuous filtration. If the water is green or winterizing failed, expect 3 to 7 days to get it clear.
Do you need to drain the pool every year?+
No. Routine draining damages the shell, adds cost to the season and wastes water. It's only justified if cyanuric acid is very high, salinity has spiked, or the lining needs repair.
How do you recover a green pool at opening?+
First adjust pH to 7.2, apply shock chlorination, run filtration continuously for 24 hours, brush walls and floor, and use a flocculant if the water turns cloudy. Then backwash and re-test before considering the opening complete.
What should you check on the filtration system when opening?+
Pump seals and gaskets, pressure gauge reading, sand or cartridge condition, selector valve, timer, and possible leaks in the equipment room. It's the best time of year to catch a breakdown before the pool is in use.
Organize your opening campaign
Plan by zone, log photos and parameters for every pool, and send the report to the owner as soon as you finish.