Plumbing Runs: How Water Circulates

Professional Pool Company — Understanding How Your Pool Moves, Filters & Heats Water

Your pool’s plumbing system is the hidden network that keeps your water clean, circulating, filtered, heated, and balanced. Although much of it is buried underground, it plays a major role in the performance and efficiency of your entire pool.

This article explains how plumbing runs work, how water moves through your system, and what each component does.

⭐ 1. The Purpose of Your Plumbing System

Your plumbing system performs four essential tasks:

✔ Circulates water to keep it moving

✔ Filters debris through your pump & filter

✔ Delivers chlorine via the salt or chlorination system

✔ Heats the water (if you have a heater or heat pump)

A well-designed plumbing system ensures:

• Clearer water
• Better energy efficiency
• Improved chemical distribution
• Longer equipment lifespan

⭐ 2. Where Water Comes From: Suction Lines

Water enters your pump through suction lines. These lines “pull” water from the pool.

Your suction system typically includes:

• Skimmer(s) — Pulls surface water and floating debris
• Main drain(s) — Pulls water from the bottom for full-depth circulation
• Spa suction (if you have a spa)
• Vacuum line (on some builds)

All suction lines run underground to the equipment pad and meet at the pump.

⭐ 3. The Pump: The Heart of the Circulation System

Your variable-speed pump moves water through the entire system.

The pump:

• Pulls water from suction lines
• Pushes water through filters, salt systems, and heaters
• Sends clean water back into the pool

Variable-speed pumps adjust RPM to improve efficiency, allowing different speeds for filtration, heating, spa, and water features.

⭐ 4. Filtration: Cleaning the Water

After the pump, water travels through the filter.

Common filter types:

• Cartridge filter (recommended) — Highest clarity, low maintenance
• DE filter — Fine filtration, more maintenance
• Sand filter — Lower clarity, inexpensive, more common in older systems

This step removes:

✔ Dirt

✔ Fine particles

✔ Most suspended debris

Clean water then moves to the sanitization and heating portion of the system.

⭐ 5. Sanitization: Salt System or Chlorine Feeder

After filtration, water flows through your salt chlorine generator (if equipped) or chlorinator.

Salt System (most common)

• Water passes through the salt cell
• The cell converts salt into chlorine
• Chlorine is returned to the pool continuously

Traditional Chlorine

• Water feeds through a tablet or liquid chlorinator
• Chlorine is delivered manually through the system

This is how your pool stays continuously sanitized.

⭐ 6. Heating: Gas Heater or Heat Pump

If you have a heating system, water flows through:

• Gas heater (fastest heating)
• Electric heat pump (energy-efficient)
• Chiller (optional — cools water in summer)

The heater raises the temperature before water is returned to the pool.

⭐ 7. Water Returns: Return Jets & In-Floor Circulation

Once water has been pumped, filtered, sanitized, and heated, it travels back to your pool through the return system.

Standard returns:

• Eyeball jets placed around the pool
• Positioned to create a circular flow pattern
• Deliver water evenly across the entire pool volume

Spa returns:

• Jets for spa therapy
• Dedicated return loop for proper pressure

Sunshelf returns:

• Low-flow returns to prevent water from becoming stagnant on shallow shelves

⭐ 8. Optional Features on Pressure Lines

Pressure lines can feed additional features:

• Waterfalls or scuppers
• Bubblers
• Deck jets
• Spillovers
• Sheer descents
• Laminar jets

These are controlled by valves at the equipment pad or by automation.

⭐ 9. The Role of Valves

Valves allow you to control water flow through each circuit.

Manual valves:

• Let you control which lines are active
• Useful for adjusting waterfall or spa flows

Automated valves:

• Controlled by smart systems (Hayward Omni)
• Adjust themselves when you enable features like “Spa Mode” or “Waterfall Mode”

Valves help balance pressure and direct water where it needs to go.

⭐ 10. Oversized Plumbing = Better Efficiency

Professional Pool Company uses oversized plumbing (typically 2.0”–2.5”) where required.

Benefits:

✔ Lower pump RPM = lower electric bill

✔ Better skimming

✔ Stronger water features

✔ Longer pump and heater lifespan

✔ Reduced pressure inside the system

Oversized plumbing is a key factor in an efficient, long-lasting pool.

⭐ 11. How Your System Protects Itself

Your plumbing system includes safeguards such as:

• Check valves — Prevent backflow
• Unions — Allow easy equipment replacement
• Air relief valves — Release trapped air
• Pressure gauges — Monitor filter health
• Bonding — Electrical safety across all plumbing and equipment

These components keep your system safe and functional.

⭐ 12. Summary: How Water Circulates Through Your Pool

1. Suction Lines

Skimmer + main drain → Pump

2. Pump

Pulls water → pushes water forward

3. Filter

Removes dirt and debris

4. Sanitization

Salt system or chlorinator adds chlorine

5. Heater (Optional)

Warms or cools water

6. Return Lines

Clean, treated water returns to the pool

This repeat cycle keeps your pool clean, balanced, and ready to enjoy.

⭐ Have Questions About Your Plumbing System?

We’re always happy to explain how your equipment works and what each component does.

👉 Ask us anytime for help understanding your system.

Updated on: 28/11/2025