A Broken Backwash Valve Would Have Drained This Pool Completely — We Caught It on the Weekly Visit

A pool we service in Frisco had a multiport backwash valve fail on the filter. Left alone, that failure would have quietly drained the entire pool — water running straight out the waste line until there was nothing left. We caught it on the weekly visit before it emptied. If we'd been coming every two weeks, the homeowner would have walked out one morning to an empty pool, a burned-out pump, and possibly a plaster shell cracking in the Texas sun.

What a Multiport Valve Does

If you have a DE or sand filter, there's a good chance you have a multiport valve — the handle on top of or beside the filter with settings like Filter, Backwash, Rinse, Waste, and Recirculate. It directs where your water goes. On the "Filter" setting (where it sits 99% of the time), water flows through the filter and back to the pool.

Inside that valve is a rubber component called a spider gasket. It seals the internal channels so water only goes where the handle tells it to. When that gasket fails, or the valve cracks, water starts leaking between channels — and depending on the failure, it can route pool water straight to the waste line and out of the system entirely.

How This Nearly Emptied the Pool

On this pool, the valve had failed in a way that was sending water toward the waste line while the pump ran. Slowly, but constantly. Every hour the pump ran on its normal schedule, the pool level dropped a little more.

Here's why this is so dangerous: it's invisible until it's a catastrophe. There's no alarm, no obvious spray, no puddle if the waste line runs to a drain. The pool just… loses water. In Frisco summer heat, a homeowner might assume it's evaporation. By the time the level drops enough to notice, you're looking at:

• A pump that's run dry — once the water drops below the skimmer, the pump sucks air, overheats, and the shaft seal and motor burn out. That's a $1,400 replacement.
• A completely drained pool — which in Texas heat isn't just inconvenient. An empty plaster or fiberglass shell exposed to sun and ground pressure can crack or, in extreme cases with high water tables, "pop" out of the ground.
• Wasted water — thousands of gallons pumped out over days, on your water bill.

Why Weekly Service Caught It and Biweekly Wouldn't Have

This is the entire case for weekly service in one story.

On a weekly schedule, the longest this failure could go unnoticed is 7 days — and we caught it faster than that because checking equipment is part of every visit. We noticed the water level was off, traced it to the valve, and stopped it before the pool dropped below the skimmer.

On a biweekly schedule, there's a 14-day gap between visits. A slow, constant drain running for up to two weeks straight is more than enough time to empty a pool below the skimmer line, burn the pump, and potentially damage the shell. The homeowner would have come home to a disaster that a 7-day cycle prevents.

That's the difference people don't see when they compare $179 weekly to a cheaper biweekly plan. You're not paying extra for one more cleaning every two weeks. You're paying for the equipment check that catches a failing valve, a leaking union, a tripped breaker, or a dropping water level before it turns into a four-figure repair. The cleaning is the visible part. The catch is the valuable part.

What We Check on Every Weekly Visit

This valve failure got caught because equipment inspection is built into every single visit, not just occasional ones:

• Water level — is it where it should be, or dropping faster than evaporation explains?
• Filter pressure — a reading that's too high or too low points to specific problems
• Valve position and condition — is the multiport handle seated right, is there weeping around the valve body?
• Pump operation — sound, prime, bubbles in the basket
• Visible leaks — unions, fittings, the equipment pad

None of this takes long. But it only works if someone is looking regularly. A problem that develops on day 2 of a 14-day cycle has 12 days to become a catastrophe. On a 7-day cycle, it has a fraction of that.

The Takeaway

Equipment doesn't fail on a schedule. A backwash valve, a pump seal, a skimmer line — these go when they go, and the damage compounds every day nobody's watching. Weekly service isn't about the pool being dirtier on day 10 than day 5. It's about the gap between "small problem" and "disaster" being short enough that we're standing there when it happens.

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