Swimming Pool On Demand

Guides · Updated Oct 31, 2026

Pool opening checklist

Opening a pool well in spring saves weeks of cloudy water and expensive chemical corrections later. Whether you open your own pool or run a route of openings for customers, this checklist walks through the job in the order that works best: clean the cover, wake up the equipment, fill and circulate, then balance the water.

1. Gather supplies before you start

Have these on hand so you don't stall halfway through: a cover pump, leaf net and skimmer, telescopic pole, wall and floor brush, a reliable test kit (a drop-based kit measuring free chlorine, pH, total alkalinity, calcium hardness and cyanuric acid is far more accurate than strips), chlorine (liquid sodium hypochlorite or a shock product), pH increaser and decreaser, alkalinity increaser (sodium bicarbonate), and any O-rings or drain plugs you removed in the fall. Teflon tape and O-ring lubricant are worth keeping in the truck.

2. Clean and remove the cover

Pump standing water off the cover first. Dragging a cover full of water and leaves into the pool is the most common way an opening goes wrong. Sweep or blow off debris, then remove the cover and lay it flat on a clean area. Rinse it, let it dry completely, and fold it loosely before storage; a cover stored damp grows mildew. Inspect safety covers for torn straps and loose anchors and note anything that needs replacing.

3. Raise the water level

Most pools are lowered for winter. Fill back to the middle of the skimmer opening. If you are filling from a well, test for metals such as iron and copper before adding chlorine; a metal sequestrant added first helps prevent staining. Note the starting water level on the service log so you can spot a leak later.

4. Reconnect and inspect the equipment

  • Plugs and fittings: Remove winterizing plugs from return lines and skimmers. Replace drain plugs on the pump, filter, heater and chlorinator.
  • Pump: Inspect the lid O-ring, lubricate it with a silicone-based pool lubricant, and fill the pump basket with water to prime.
  • Filter: Reinstall cartridges or check sand and DE grids. Start with a clean filter; a backwash or cartridge rinse after the first few days removes the dirt the startup stirs up.
  • Heater and salt cell: Reconnect, but wait to fire a heater until the water is circulating properly. Inspect salt cells for scale.
  • Electrical: Confirm GFCI protection trips and resets before running anything.

5. Start circulation

Open the valves, turn on the pump, and confirm it primes within a few minutes. Look for air bubbles in the pump basket (often a loose lid or low water), leaks at unions, and pressure on the filter gauge. Record the clean-filter starting pressure; when it rises about 8–10 psi above that number, it's time to clean the filter. Run circulation continuously for the first 24–48 hours.

6. Clean the pool

Skim leaves off the surface, brush the walls, steps and floor, and vacuum. Heavy debris on the floor can be vacuumed to waste on sand and DE filters so it doesn't load the filter. Empty skimmer and pump baskets often during the first day.

7. Test and balance the water

Once the water has circulated for several hours, test and adjust in this order, because each step affects the next:

  1. Total alkalinity: target roughly 80–120 ppm. Alkalinity buffers pH, so set it first.
  2. pH: target 7.4–7.6. Low pH is corrosive; high pH reduces chlorine effectiveness and promotes scale.
  3. Calcium hardness: typically 200–400 ppm for plaster pools; vinyl and fiberglass can run lower.
  4. Cyanuric acid (stabilizer): about 30–50 ppm for outdoor chlorine pools; saltwater pools often run 60–80 ppm. CYA usually stays in the water over winter, so test before adding more.
  5. Chlorine: shock to break up winter contaminants. A common target is to raise free chlorine to roughly 40% of your CYA level and hold it there until the water is clear and chlorine holds overnight.

Add chemicals one at a time with the pump running, and allow time to circulate before retesting. Never mix chemicals together in a bucket.

8. Handling green or cloudy water

A green opening is common, not a disaster. Keep brushing daily, keep free chlorine at shock level, run the filter continuously and clean it as pressure rises. Most pools clear in a few days. Clarifier can help a cloudy pool once the algae is dead, but it doesn't replace sanitizer.

9. Final checks before swimming

Wait until free chlorine is back in the normal range (generally 1–3 ppm for unstabilized pools, or higher in proportion to CYA), pH is in range, and you can clearly see the main drain. Check ladders, handrails, lights and safety equipment.

10. Write it down

Record starting readings, chemicals added, equipment notes and anything a customer needs to know. For pool service companies, sending the homeowner a photo report of the opening sets expectations for the season and makes the next visit faster. Questions for a pro? Write to support@swimmingpoolondemand.com.

Pool pros: log every reading and send photo reports with Swimming Pool On Demand.