How to Open Your Pool in Spring: A Complete Guide

Opening your pool in spring is one of the most satisfying moments of the year — but doing it right makes the difference between a smooth start and weeks of fighting cloudy water. Here is the complete guide from 20+ years of spring openings across Lake Country.

When to Open Your Pool in Wisconsin

In southeastern Wisconsin, most pool owners open between late April and mid-May. The key indicator is not a specific date — it is consistent daytime temperatures above 70°F. Opening too early means spending more on chemicals to fight algae growth. Opening too late means algae may already be established under your cover.

Step 1: Clean and Remove the Cover

Before pulling the cover off, use a cover pump to remove standing water and sweep off leaves and debris. This prevents all that gunk from falling into your pool. Once the cover is clear, carefully remove it, hose it off, let it dry completely, and fold it for storage.

Step 2: Reconnect Your Equipment

Reinstall any drain plugs you removed during closing. Reconnect your pump, filter, heater, and any chlorinators or salt systems. Check all connections for cracks, leaks, or wear. If anything looks questionable, it is better to address it now than mid-season.

Step 3: Fill the Pool and Inspect

Top off the water level to the middle of your skimmer opening. While the pool is filling, inspect the liner or surface for damage, check the skimmer basket, and make sure all returns are open and flowing.

Step 4: Start the Pump and Filter

Prime your pump if necessary, then start the system. Let it run for at least 24 hours to circulate the water and filter out initial debris. Check for proper flow and listen for unusual sounds.

Step 5: Test and Balance Your Water

This is the most important step. Test your water for pH, total alkalinity, calcium hardness, and sanitizer levels:

• pH: 7.2 – 7.6
• Total Alkalinity: 80 – 120 ppm
• Calcium Hardness: 200 – 400 ppm
• Free Chlorine: 1 – 3 ppm

Step 6: Shock the Pool

After balancing your chemistry, shock the pool with a high dose of chlorine to kill bacteria and oxidize contaminants that built up over winter. Run the pump overnight after shocking and do not swim until chlorine levels drop back below 3 ppm.

Step 7: Add Algaecide and Clarifier

Once the shock has done its work, add an algaecide as a preventive measure and a clarifier to help your filter capture fine particles. Within 24–48 hours, your water should be clear and inviting.