Is It Better to Cover a Pool or Leave It Open?
If covering your pool takes five minutes, why do so many people leave it open all season?
Usually it's one of two reasons: they don't think it makes a real difference, or the cover they tried once was a hassle to use. Both are worth addressing directly, because the actual answer isn't close — leaving a pool open costs measurably more in water, chemicals, energy, and eventually the liner itself.
What Happens When You Leave a Pool Open
An open pool is constantly losing something — usually more than one thing at once.
Water. Evaporation is the largest source of water loss for an uncovered pool. The EPA's WaterSense program estimates a typical uncovered residential pool can lose between 12,000 and 31,000 gallons per year to evaporation alone, depending on climate and pool size. (Source: EPA WaterSense)
Chemicals. Every gallon that evaporates takes dissolved chlorine, algaecide, and pH balancers with it, which means an open pool needs more frequent — and more expensive — rebalancing.
Heat, if the pool is heated. The Department of Energy identifies evaporation as the single largest source of energy loss in a heated pool, since each pound of warm water that evaporates carries its heat with it.
Debris and algae growth. Direct, constant sunlight accelerates algae growth, and an open surface collects leaves, pollen, and dirt continuously — both of which mean more time spent skimming, filtering, and shocking the water.
UV exposure on the liner. Above ground pool liners degrade faster under constant UV exposure, which is one of the leading causes of premature liner failure.
What a Cover Actually Changes
Covering the pool doesn't eliminate these issues, but it meaningfully reduces all of them at once.
The EPA states a properly used pool cover can prevent up to 95% of evaporation. (Source: EPA WaterSense) The Department of Energy puts typical heating cost savings from consistent cover use at 50–70%, chemical consumption reduction at 35–60%, and make-up water reduction at 30–50%. (Source: U.S. Department of Energy) On the liner side, industry data from Angi puts average liner lifespan around 10 years, with a five-to-15-year range — and consistent UV exposure is repeatedly cited as one of the variables that pushes a liner toward the shorter end. (Source: Angi)
We break this down in full, including the exact dollar-and-cents math, in Is a Pool Cover Worth It? The Real Cost Savings, Backed by Data.
When Leaving It Open Might Actually Make Sense
To be fair to the other side of this: covering isn't always the deciding factor.
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Daily or near-daily use during peak season. If you're covering and uncovering the pool every single day anyway, the marginal water/heat savings shrink, though debris and UV protection still apply whenever it is covered.
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Very short setup windows. A pool filled for a week and then drained doesn't have time to accumulate the same evaporation or UV damage as one left up all summer.
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A cover that doesn't fit well. A loose or undersized cover that lets in as much debris and evaporation as an open pool isn't actually delivering the benefit — in that case, the problem is the cover, not the concept. Our guide to choosing the right above ground pool cover covers how to avoid that.
Covered vs. Open Pool Comparison
| Factor | Pool Left Open | Pool Covered (Consistently) |
|---|---|---|
| Annual evaporation loss | 12,000–31,000 gallons | Up to 95% less |
| Heating costs (if heated) | Full ongoing cost | 50–70% lower |
| Chemical consumption | Full ongoing cost | 35–60% lower |
| Debris/algae accumulation | High, constant | Significantly reduced |
| Liner UV exposure | Continuous | Significantly reduced |
| Typical liner lifespan | Tends toward 5–7 years | Tends toward 10–15 years |
| Effort required | None (but higher ongoing maintenance) | A few minutes per use |
Stats Worth Knowing
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A pool cover can prevent up to 95% of water loss from evaporation. (Source: EPA WaterSense)
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Consistent cover use cuts heating costs by 50–70% and chemical use by 35–60%. (Source: U.S. Department of Energy)
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Average pool liner lifespan is about 10 years, with UV exposure named as a top factor in shortening that range. (Source: Angi)
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Frequently Asked Questions
Is it bad to leave a pool uncovered all the time?
It's not damaging in the way skipping maintenance is, but it's costly — more water and chemical loss, faster algae growth, more UV wear on the liner, and if the pool is heated, a significantly higher energy bill.
Does covering a pool actually stop algae?
A cover blocks the direct sunlight algae needs to grow quickly, which meaningfully slows growth. It doesn't replace chemical maintenance entirely, but it reduces how hard that maintenance has to work.
How much money does covering a pool actually save?
It depends on climate, pool size, and whether the pool is heated, but the EPA and DOE figures above — up to 95% less evaporation, 50–70% lower heating costs, 35–60% lower chemical use — typically add up to real, noticeable seasonal savings for anyone using a cover consistently.
Is it worth covering a pool I only use a few times a week?
Yes, in most cases. Even with regular use, covering the pool the rest of the time still captures the bulk of the evaporation, debris, and UV benefit — you only lose ground during the hours it's actually open.
Addressing Common Objections
The most common reason people skip covering their pool isn't that they don't believe it helps — it's that a past cover was a hassle to put on and take off, so it ended up staying in the garage. That's usually a sizing or fastening-system problem, not a reason to skip covers altogether. A properly fitted cover with a ratchet strap system takes a few minutes to secure and remove, and the time cost is small compared to what's saved in water, chemicals, and cleaning.
Limitations to Consider
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A cover doesn't replace water testing and chemical maintenance — it reduces how much work that maintenance requires, but doesn't eliminate it.
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Ill-fitting covers underperform. The savings figures above assume a cover that's properly sized and consistently used; a loose or damaged cover won't deliver the same results.
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Heated pools see the largest financial benefit. Unheated pools still benefit from reduced evaporation, chemical use, and debris, but the dollar savings are smaller without the heating-cost factor.
What Customers Are Saying
"Covered my pool last summer and opened it in March to crystal-clear water — barely needed any chemicals." — joey
"Two years in and it's still going strong, and far more affordable than the covers I used to go through constantly." — Emma Moore
"Easy to install, much faster than my old cable-style cover, and shipped in just three days." — Mark T
Find the Right Pool Cover for Your Pool
Whether your pool is round, oval, or rectangular, we have a cover built to fit it properly and hold up season after season.
Final Thoughts
Leaving a pool open isn't a neutral choice — it's an ongoing cost in water, chemicals, energy, and liner life, backed by EPA and Department of Energy data. A properly fitted cover, used consistently, cuts nearly all of that cost for a few minutes of effort each time. The exceptions are narrow: very short-term setups, daily use where the pool is rarely closed anyway, or a cover that doesn't fit well enough to do its job. For most above ground pool owners, covering it is the easier and cheaper choice, not just the tidier one.
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