Pool Closing Mistakes That Cost Minnesota Owners in Spring
The pool closing mistakes that cost Minnesota owners the most each spring — timing, water level, plumbing lines, chemistry, and cheap covers.
What Are the Most Common Pool Closing Mistakes in Minnesota?
The five mistakes that cost Minnesota pool owners the most every spring are closing too early or too late, getting the water level wrong for your cover type, leaving water in the plumbing lines, skipping water chemistry before you close, and covering the pool with a cheap or ill-fitting cover. Every one of them looks harmless in October and shows up in April as a cracked return line, a stained liner, a torn cover flapping in the yard, or, worst case, a shattered length of underground pipe that has to be dug up and replaced. These are the five we see most every spring. The good news is each one is entirely avoidable with the right timing and the right steps, whether you close the pool yourself or have us do it. Here's what actually goes wrong, and what it costs when it does.
Mistake #1: Closing Too Early or Too Late
Minnesota's swim season runs into September, and code frost depth in the Twin Cities area is 42 inches (60 inches up in northern Minnesota); real frost can push deeper in a severe winter, so the safe closing window is genuinely September into October. The first cool weekend is usually too early to close, and closing "whenever you get around to it" is usually too late. Close too early and you're just giving up warm swim weeks for no real gain. Close too late and you're gambling against an overnight freeze catching you mid-project, with water still sitting in the return lines, skimmer lines, or main drain when the temperature drops. That's how a routine closing turns into cracked underground plumbing — the single most expensive spring repair we see, often running into the thousands of dollars once you factor in excavation to reach the break. The safest rule of thumb: start watching overnight lows once you hit late September, and get the pool closed before a hard freeze shows up in the forecast. Waiting past that point is where the damage starts. If you're not sure when to pull the trigger, call before a hard freeze shows up in the ten-day forecast — that's the exact window our service team works from every fall.
Mistake #2: Getting the Water Level Wrong
Water level is one of those details people either skip or overcorrect, and both directions cause real damage. There's no single universal number here — the right level comes from your cover manufacturer's spec, measured from the pool's top edge rather than the skimmer opening. LOOP-LOC, for example, calls for 15–18 inches below the top edge under a mesh cover, 12–16 inches under a solid one; other brands set their own numbers. Get the level wrong for your cover and you're wrong for the plumbing too. Leave it too high and ice expanding inside the skimmer can crack the housing, a repair that's avoidable and annoying in equal measure. Drain it too low, or drain the pool completely, and you remove the water weight that helps hold the pool structure in place against Minnesota's freeze-thaw ground pressure over winter, which can shift walls or damage a vinyl liner. The fix takes ten minutes with a pump and a tape measure, but it's one of the steps people either forget entirely or get backwards, assuming lower is always safer. Check your cover's actual spec and you avoid both failure modes: a cracked skimmer in spring, or structural movement that costs far more to correct.
Mistake #3: Not Fully Blowing Out the Plumbing Lines
Every return line, the skimmer line, and the main drain line have to be completely emptied of water and plugged so groundwater or condensation can't creep back in, and this is the step that makes a professional closing worth what it costs. Clearing those lines takes compressed air, and compressed air in pool plumbing can separate fittings and cause serious injury when it's done wrong; equipment manufacturers state that risk bluntly in their own manuals — this is a pro step rather than a weekend project. The main drain gets blown clear and air-locked with the valve closed, a different process from simply emptying and plugging a return line, and one that takes the right equipment and sequence to do safely. Any water left behind in that underground plumbing freezes, expands, and cracks the pipe, and because it's buried, you won't know until spring, when you turn the system back on and find a leak, or a section of pipe has to be dug up and replaced entirely. This single failure accounts for the most expensive repair bills we see each spring, routinely landing in the thousands once you add excavation and pipe repair together. Don't call the closing finished until every line is verified empty and every plug is in place.
Mistakes #4 and #5: Skipping Water Chemistry and Closing Under a Cheap Cover
Balancing the water before you close feels optional, since the pool sits under a cover for six months anyway, but unbalanced water turns into a green, stained mess by April. Skip the pre-close pH, alkalinity, and algaecide steps, and algae spores get a six-month head start with no circulation to fight them. What comes out from under the cover is often a pool needing a full shock treatment, extra filtration runtime, and sometimes stain removal on the plaster or liner, all pricier than the ten minutes it takes to test and balance beforehand. Salt system owners have one extra step: run the system for a day after the closing chemicals go in, so they distribute evenly instead of pooling in one spot. The cover matters just as much. A thin tarp-style cover, or one that doesn't fit your pool's exact dimensions, is a mistake that compounds all winter: gaps let wind work it loose, weak material sags under wet snow and tears, and a poorly secured cover can shift entirely, leaving the pool open to leaves, branches, and animals for months. A mesh safety cover, professionally sized and anchored with straps, springs, and deck anchors, is the standard we install — it drains snowmelt instead of pooling it, and holds up to a full Minnesota winter. Water-bag covers are a different, cheaper product; a properly anchored safety cover does a job they can't. A cheap or failed cover means a different spring cleanup: saturated debris, staining from decomposed leaves, and sometimes a liner replacement from a shifted cover's cable.
What These Closing Mistakes Really Cost You in Spring
Stack these five mistakes up and a familiar pattern shows up: a small shortcut in October becomes a bigger bill in April. A cracked skimmer from bad water level is a modest repair. A cover replacement runs from a few hundred dollars into four figures depending on size and material, so it's worth confirming current pricing before you buy either way. Algae and staining from skipped chemistry mean extra chemicals and labor hours before the pool is swimmable, a modest cost on its own, but real money and real delay once it stacks up with everything else. Cracked underground plumbing from lines that weren't blown out fully is in a different category entirely: that's the repair that routinely runs into the thousands once excavation is involved, and it's the one item here worth calling genuinely expensive rather than just annoying. Avoiding all five just takes doing the closing in the right order, at the right time, with the right level of care, which is exactly what a professional closing is built to catch before it costs you.
Skip the Spring Repair Bill — Let Us Close It Right
Every mistake on this list is preventable, and most of them take only a few extra minutes of attention during closing. If you'd rather not be the one testing water chemistry in 40-degree weather or double-checking that every line is fully blown out, our professional closing service covers chemistry, cleaning, plumbing blow-out, equipment protection, and a properly fitted cover, so nothing gets rushed or skipped and none of these five mistakes make it into your pool over the winter. September is when our closing calendar fills fastest: most owners call the week the first frost warning hits their phone, and by then the slots that still fit your timeline are already gone. Booking early means we can close on your schedule instead of squeezing you in between other calls once the forecast turns. Call (651) 653-6807 now and get on the schedule before that happens.