How Do I Plumb a Skimmer in a New Inground Pool?

So, you’ve just had a beautiful new inground pool installed—or maybe you’re tackling the build yourself—and now you’re wondering: How do I plumb a skimmer in a new inground pool? You’re not alone. Getting the skimmer plumbing right is critical for water clarity, filtration efficiency, and long-term pool health. A poorly plumbed skimmer can lead to weak suction, debris buildup, or even system failure. But don’t worry—we’ll walk you through it clearly, safely, and correctly, whether you’re a DIYer or just want to understand what your contractor should be doing.

Why Is Skimmer Plumbing So Important?

The skimmer is your pool’s first line of defense against floating debris like leaves, bugs, and sunscreen residue. It draws surface water into the filtration system, typically capturing up to 75–80% of all debris before it sinks (National Swimming Pool Foundation, 2023). If the plumbing isn’t sized, sloped, or sealed properly, you risk:

• Reduced water flow
• Air leaks causing pump cavitation
• Inefficient filtration
• Higher energy bills

In short: good skimmer plumbing = cleaner water + lower maintenance.

What Tools and Materials Do You Need?

Before you start, gather these essentials:

• PVC pipe (typically 2-inch diameter for residential pools)
• PVC primer and cement
• Skimmer body (with faceplate and weir door)
• Pipe cutter or hacksaw
• Measuring tape
• Level
• Teflon tape (for threaded fittings, if any)
• Sand or gravel (for bedding under pipes)

💡 Pro Tip: Always check local building codes. Some municipalities require specific pipe types (e.g., Schedule 40 PVC) or permit inspections before backfilling.

Step-by-Step: How to Plumb a Skimmer in a New Inground Pool

Follow these steps carefully during the pool shell installation phase—before concrete decking or backfilling.

Step 1: Position the Skimmer Correctly

• Install the skimmer on the downwind side of the pool (prevailing wind direction in your area).
• Ensure the top of the skimmer is level with the waterline when the pool is full.
• Most skimmers are placed 6–12 inches below the coping.

According to the Association of Pool & Spa Professionals (APSP), improper skimmer height is among the top 3 causes of poor surface skimming.

Step 2: Connect the Skimmer to the Main Drain (Optional but Recommended)

Many modern pools use a dual suction system: skimmer + main drain. This improves safety (reducing entrapment risk) and circulation.

• Run a 2-inch PVC line from the skimmer’s bottom outlet to the main drain.
• Use a diverter valve inside the skimmer to balance suction between skimmer and drain.

⚠️ Safety Note: Since the Virginia Graeme Baker Pool & Spa Safety Act (2007), all public and residential pools must have anti-entrapment systems. Dual suction helps meet this standard.

Step 3: Run the Return Line to the Equipment Pad

• From the skimmer’s side outlet (or dedicated suction port), run a continuous 2-inch PVC pipe to the pump.
• Maintain a consistent downward slope (1/4 inch per foot) toward the equipment to prevent air pockets.
• Avoid sharp 90-degree elbows; use two 45-degree bends instead to reduce flow resistance.

Step 4: Dry-Fit Before Gluing

• Assemble all pipes and fittings without glue first.
• Check alignment, slope, and clearance from rebar or pool walls.
• Mark cut points with a pencil.

Step 5: Prime and Cement the Joints

• Apply purple PVC primer to both pipe and fitting.
• Follow immediately with clear PVC cement.
• Insert pipe fully, then give a 1/4 turn to spread adhesive evenly.
• Hold for 30 seconds to prevent slippage.

🌡️ Ideal working temperature: 60–90°F (15–32°C). Cold weather slows curing and weakens bonds.

Step 6: Pressure Test the System

• Cap all open ends.
• Use a manual air pump or water pressure test kit.
• Pressurize to 15–20 PSI and hold for 15 minutes.
• No pressure drop = leak-free system.

Only after passing this test should you proceed to backfill.

Common Mistakes to Avoid

For more on fluid dynamics in pool systems, see Wikipedia’s entry on hydraulic head, which explains pressure and flow principles relevant to plumbing design.

Skimmer Plumbing: Single vs. Dual Suction

Many homeowners ask: Should I plumb my skimmer alone or with a main drain?

Single Skimmer Setup
✅ Simpler, cheaper
❌ Higher entrapment risk, less balanced circulation

Dual Suction (Skimmer + Main Drain)
✅ Safer, better debris capture, meets modern codes
❌ Slightly more complex plumbing

📊 A 2022 study by Pool & Hot Tub Alliance found that dual-suction pools had 32% fewer service calls related to clogs or pump issues over a 3-year period.

How Many Skimmers Do You Need?

Rule of thumb: One skimmer per 400–500 square feet of surface area.

• 12′ x 24′ pool (288 sq ft) → 1 skimmer
• 20′ x 40′ pool (800 sq ft) → 2 skimmers

Place skimmers opposite each other or at diagonal corners for optimal cross-circulation.

FAQ Section

Q1: Can I plumb a skimmer after the pool is finished?

A: Technically yes, but it’s extremely difficult and costly. You’d need to break through decking, reroute pipes, and risk damaging the shell. Always plumb during initial construction.

Q2: What size PVC pipe should I use for the skimmer line?

A: For most residential inground pools (10,000–30,000 gallons), 2-inch Schedule 40 PVC is standard. Smaller pools (<10,000 gal) may use 1.5″, but 2″ is preferred for future-proofing.

Q3: Should the skimmer line go directly to the pump or through a valve?

A: It should connect to a suction-side multiport valve or diverter. This lets you isolate the skimmer for maintenance or adjust flow between skimmer and main drain.

Q4: How deep should the skimmer plumbing be buried?

A: At least 18–24 inches below grade to avoid freeze damage (in cold climates) and protect from landscaping tools. Always bed pipes in sand to prevent stress cracks.

Q5: My skimmer isn’t pulling water—what’s wrong?

A: Common causes:

• Air leak in suction line (check glued joints)
• Clogged weir or basket
• Pump lid o-ring not sealed
• Improper pipe slope causing air lock

Q6: Do I need a separate skimmer for an attached spa?

A: Yes. Spas generate more oils and require dedicated skimming due to higher bather load and temperature. Never share a skimmer between pool and spa.

Conclusion

Knowing how to plumb a skimmer in a new inground pool isn’t just about connecting pipes—it’s about engineering clean, safe, and efficient water flow from day one. By following these professional-grade steps, avoiding common pitfalls, and respecting plumbing physics, you’ll enjoy crystal-clear water with minimal effort for years to come.

If this guide saved you time or confusion, share it with a fellow pool owner on Facebook or Pinterest! And if you’re unsure about any step, consult a licensed pool contractor—your investment deserves expert care.