Skimmer and Main Drain Service

Why this matters

Skimmers and main drains are the two pickup points for pool water in the circulation system. The skimmer pulls surface water; the main drain pulls bottom water. Both components are essential for circulation and both are governed by the Virginia Graeme Baker (VGB) Pool & Spa Safety Act of 2007 (Public Law 110-140) which mandates anti-entrapment compliance. Service on these components is recurring (cleaning, parts replacement) and the safety requirements are non-negotiable.

When to use this procedure

• Routine cleaning during weekly service
• Inspection during quarterly service
• Replacement of weir, cover, basket, or fitting
• Diagnostic for suction-side issues
• Compliance verification on a pool you've taken over from another service

The Virginia Graeme Baker (VGB) Act

The VGB Act requires every public pool drain cover to be ANSI / APSP / ICC-7 compliant - anti-entrapment design. Residential pools built or significantly renovated after the act may also be subject to local code requirements based on it. Specifically:

• Single main drain installations must have an additional safety device (vacuum release device, gravity drain conversion, or dual drain installation)
• Drain covers must be ANSI / APSP / ICC-7 certified
• Damaged or missing drain covers must be replaced before the pool is used

The act is named after Virginia Graeme Baker, a 7-year-old who drowned in 2002 due to suction entrapment in a hot tub. Service companies that work on pool drains have ethical and legal responsibilities under this law.

Skimmer components

A typical residential skimmer has:

1. Skimmer body - the housing that's installed in the pool wall
2. Weir - the flap at the water intake that traps surface debris and protects against backflow
3. Skimmer basket - the removable basket inside the skimmer that catches leaves and large debris
4. Lid / cover - the deck-level cover (some skimmers, not all)
5. Equalizer line port - second port that draws water from below the basket level (anti-vortex)
6. Suction line port - outlet to the pump
7. Diverter / float valve - some skimmers have a float that switches between skimmer and main drain

Main drain components

1. Drain sump - the cavity at the bottom of the pool
2. Anti-entrapment cover - the safety-rated cover bolted over the sump (VGB compliant)
3. Suction line - the underground pipe to the pump
4. (Optional) Safety vacuum release - backup safety device

Procedure - skimmer routine service

Step 1: Open the lid

1. Remove deck-level skimmer cover
2. Verify there's no immediate hazard (sharp glass, dead animal, exposed electrical)

Step 2: Remove and inspect basket

1. Pull the basket up and out
2. Empty contents into the trash
3. Inspect for:

• Cracks in the basket
• Heavily compressed debris (indicates dripper / filter feed)
• Foreign objects (toys, etc. to set aside for customer)

1. Rinse the basket with the hose if very dirty

Step 3: Inspect the weir

1. Look at the weir flap inside the skimmer
2. Verify it swings freely
3. Check for cracks or damage
4. Replace if broken

Step 4: Check the equalizer line port

1. Verify the equalizer port (often the second hole below the basket level) isn't blocked
2. The equalizer prevents pump cavitation when water level drops
3. Some pools have this port closed or sealed; verify per the design

Step 5: Verify the lid seal

1. The lid should sit flat
2. No standing water inside the lid recess (would indicate drainage issue)
3. Verify the lid hasn't been damaged

Step 6: Test the skimmer's flow

1. With the pump running, observe water entering the skimmer
2. Strong, steady draw = skimmer working
3. Weak draw or air bubbles = problem upstream (covered in pump priming diagnostic)

Step 7: Reassemble

1. Replace the basket
2. Replace the lid
3. Document

Procedure - main drain service

Step 1: Visual inspection

1. With the pump running, the main drain should be drawing water visibly
2. Inspect the cover for:

• Cracks
• Missing screws
• Anti-entrapment certification mark visible
• Date of manufacture (covers have a service life - verify per manufacturer)

1. Cover replacement schedule varies by manufacturer (typically 5-10 years)

Step 2: Underwater inspection (when needed)

For verification:

1. Use a diving mask and snorkel
2. Verify the drain cover is intact and secured
3. Verify all mounting screws are in place
4. Verify no obvious damage to the sump

Step 3: Cover replacement (if needed)

If the drain cover is cracked, missing, or past its service life:

1. Pool service may not be the right scope for this work - many states require a licensed contractor for underwater work or drain modifications
2. The pump MUST be off before any work on the drain (entrapment risk)
3. Replacement cover MUST be VGB-compliant
4. Cover specifications must match the original drain (flow rating, mounting pattern)

If the service company performs this work:

1. Drain pool to expose the main drain (or work underwater with appropriate safety)
2. Remove old cover
3. Inspect sump and mounting screws / threads
4. Install new VGB-compliant cover with manufacturer's torque spec
5. Photograph the installation
6. Document with the customer file

Skimmer common issues

Skimmer not pulling water:

1. Water level below the skimmer mouth - add water
2. Skimmer weir stuck closed - clean / replace
3. Basket full - empty
4. Diverter / valve set wrong - open the skimmer line
5. Air leak on the suction line - see pump-priming diagnostic

Skimmer leaks visible from outside the pool:

1. Skimmer body cracked - replacement requires excavation and re-mortar
2. Skimmer collar separated from pool wall - common settlement issue; repair as a specialty job

Skimmer lid won't sit flat:

1. Debris under the lid - clear
2. Deck around the lid has settled - major repair
3. Lid is damaged - replace

Skimmer basket damaged:

1. Replace with manufacturer's part (color and style sometimes vary)
2. Some baskets are universal-fit; verify before ordering

Main drain common issues

Drain cover missing:

• IMMEDIATE safety hazard
• Close the pool to swimmers until corrected
• Replace before any swimming

Drain cover broken:

• Replace immediately
• Document the date of damage and replacement
• Customer file note

Drain not pulling water:

References

• Virginia Graeme Baker Pool & Spa Safety Act (Public Law 110-140, 2007)
• ANSI / APSP / ICC-7 - Standard for Suction Entrapment Avoidance in Swimming Pools, Wading Pools, Spas, Hot Tubs, and Catch Basins
• CPSC Pool Safely campaign documentation
• IAPMO Uniform Swimming Pool, Spa, and Hot Tub Code
• ANSI / APSP / ICC-1 - Standard for Public Swimming Pools (Section 5.1)
• Manufacturer documentation for skimmers and drain covers (Hayward, Pentair, Custom Molded Products)
• Manuall internal: Pool Equipment Diagnostic Tree, Pool Equipment Sizing, Pool Safety Customer Education