How Often Should I Drain My Swimming Pool?

Quick Answer: Most experts recommend draining your swimming pool every 2–3 years. Over time, minerals, chemicals, and contaminants build up, making it harder to keep water clear and balanced. In Arizona and Phoenix, where water is especially hard and evaporation is extreme, draining closer to every 2 years is often best.

Why Pools Need Draining

Your pool water may look clean, but it gradually accumulates substances that don’t fully go away. Every refill, chemical adjustment, or splash leaves behind stabilizers, minerals, and organic material. Over time, this creates what professionals call “tired water.”

Here’s why draining is essential:

• Chemical saturation: Chlorides, cyanuric acid (CYA), and total dissolved solids (TDS) build up, reducing chemical effectiveness.
• Mineral accumulation: Hard water leaves calcium, which creates cloudy water and white scale.
• Persistent algae and organics: Some contaminants linger despite chlorine treatment.
• Fresh start: Only new water can fully reset water chemistry once saturation occurs.

*The Centers for Disease Control (CDC) notes that proper water balance is essential for safety and that excess stabilizers and contaminants make chlorine less effective.

When to Drain Your Pool Based on Climate

The general guideline for draining swimming pools is every 2–3 years, but your local climate may impact the timing:

• Every 2 years: Best for pools in hot, hard-water regions (like Arizona) or heavily used pools.
• Every 3 years: Reasonable in milder climates with moderate usage.
• Beyond 3 years: Not recommended. Calcium, stabilizers, and TDS levels typically become unmanageable.

The reason this 2–3 year cycle works is because water chemistry naturally drifts out of balance over time. Even with careful maintenance, minerals and stabilizers accumulate until the water can no longer be adjusted within safe ranges. The Pool & Hot Tub Alliance (PHTA) publishes standards for balanced pool water, including:

• Calcium hardness: 200–400 ppm (acceptable range 150–1000 ppm)
• pH: 7.4–7.6 (acceptable range 7.2–7.8)
• Total alkalinity:80–120 ppm (acceptable range 60–180 ppm)

When values like calcium hardness or stabilizer drift far beyond these ranges, chemical adjustments are no longer enough. As water chemistry experts at Taylor Technologies explain, the only practical correction is to drain and refill with fresh water (Taylor Technologies: Understanding & Managing Calcium Hardness).

Why Arizona Pools Need More Frequent Draining

Pools in Arizona age faster than pools in other parts of the country because of three key factors:

• Hard water: Local tap water contains high levels of calcium, which quickly saturates pool water.
• Extreme evaporation: Hot, dry weather accelerates evaporation, leaving minerals concentrated behind.
• Year-round use: Unlike seasonal pools in colder states, Arizona pools are used almost nonstop, putting constant stress on water chemistry.

Because of these conditions, Arizona homeowners should follow a 2-year draining and acid washing schedule to keep pools clean and surfaces protected.

Risks of Draining Too Often vs. Waiting Too Long

Draining too often can cause problems:

• Exposed plaster or tile may crack in sun and heat.
• Empty pools with a high water table risk “popping” or shifting.
• Water waste increases costs and environmental impact.

Waiting too long also has consequences:

• Calcium scaling and stains may become permanent.
• High stabilizer (CYA) levels reduce chlorine effectiveness.
• Cloudy, dull water that’s difficult to balance.
• Equipment stress, lowering pump and heater lifespans.

Signs That It's Time to Drain

1. White Scaling Along Tile or Plaster

Chalky white deposits at the waterline or on plaster surfaces indicate calcium buildup, a common sign your pool water is oversaturated and ready for replacement.

2. Cloudy or Dull Water That Won’t Clear

If your pool water stays cloudy despite chemical adjustments, it’s often caused by high dissolved solids or stabilizer levels that require draining to correct.

3. Recurring Algae Blooms

Algae that keeps returning even with proper chlorine treatment usually means stabilizer levels are too high, reducing chlorine’s effectiveness and signaling the need for new water.

4. High Test Readings for Calcium or Stabilizer

Water tests showing calcium hardness above 400 ppm or stabilizer (CYA) above 100 ppm mean the chemistry is out of balance and water replacement is necessary.

5. Water Feels “Hard” and Leaves Residue

If swimming feels uncomfortable and water leaves residue on skin or stone, excess minerals are present. Draining helps reset balance and prevents further scaling damage.

The Added Value: Combine Draining with an Acid Wash

One of the biggest advantages of draining your pool is that it allows for an acid wash. This professional cleaning process removes stubborn stains, calcium deposits, and algae embedded in plaster or concrete surfaces.

What is Acid Washing?

Acid washing uses a diluted muriatic acid solution to strip away a thin layer of plaster. This removes discoloration, scale, and organic buildup that regular brushing or chemicals can’t fix.

Benefits of Acid Washing

• Restores brightness and color to your pool surface.
• Removes calcium scale and stains caused by hard water.
• Kills algae spores and hidden organic buildup.
• Makes new water easier to maintain by starting fresh.

How Often Should Pools Be Acid Washed

Just like draining, an acid wash is best performed every 2–3 years. In Phoenix and other hard-water areas, this frequency helps stay ahead of calcium buildup and keeps the pool looking its best.

How to Drain a Swimming Pool Safely

Draining a pool is not as simple as pulling the plug. Done incorrectly, it can damage your pool or property.

Best practices include:

• Check groundwater levels before draining to prevent structural damage.
• Avoid extreme heat when plaster can crack in direct sunlight.
• Use a submersible pump instead of built-in plumbing.
• Discharge water responsibly so it doesn’t overwhelm storm drains or neighbor’s yards.
• Partial drains can sometimes refresh water safely if a full drain isn’t possible.

Because of these risks, most homeowners rely on professional pool draining services which ensures safe, eco-conscious water replacement.

Fast FAQ on Pool Draining

Q: How often should I drain my swimming pool?

A: Every 2–3 years, with Arizona pools leaning closer to every 2 years.

Q: Should I acid wash when I drain?

A: Yes — combining draining with an acid wash every 2–3 years removes stains and scale while resetting your pool.

Q: Why drain at all if I can just add more chemicals?

A: Eventually water becomes saturated with minerals and stabilizers that chemicals can’t overcome. Draining gives you a fresh start.

Q: Can I drain my pool myself?

A: While possible, DIY draining carries risks. Professional services ensure safe, efficient, and environmentally responsible results.

In Summary

So, how often should you drain your swimming pool? The answer is usually every 2–3 years — closer to 2 years in places like Phoenix, where hard water and evaporation speed up water saturation.

Pairing your drain with an acid wash every 2–3 years maximizes the benefit, giving you fresh water and a refreshed pool surface at the same time.

For Arizona homeowners, consider professional pool draining and pool acid washing services which provide a safe, eco-friendly, and professional way to keep your pool looking beautiful and running smoothly year after year.