You don’t need to be an expert to know that if your pool is losing an inch of water or more a day, that you may have a water leak or some other issue causing such rapid loss of water.
Now to be fair, if you’re a first-time pool owner, you might think that topping off your pool water every other day is normal, but that really depends on your situation.
How often you have to add water to your pool depends on various factors such as temperature, humidity, wind, if you’re using a pool cover, how often your pool is getting used, rain, and leakage. How many of these factors are affecting your pool will determine how often you need to top it up. Under normal conditions, water should be added every 7-10 days; you can wait as long as two weeks if conditions are favorable.
It’s not a good idea to let the water level fall too low because your pool pumps can get damaged if they suck in air.
Keep reading on, and we’ll discuss in more detail the factors that can cause your pool water to drop to help you understand whether your water loss is within a normal range or if something is wrong.
Factors that can cause water loss
We learned all the way back in elementary school that the rate of water evaporation increases as the temperature increases. Not that water can’t evaporate at lower temperatures, just that it will be slower compared to warmer temperatures.
Following this logic, if the temperature is as high as 105°F (40.6°C) outside where you live, compared to a pool owner living where it’s only 80°F (26.7°C), it should not be a surprise that you will have to add water more often than the pool owner living in the cooler climate.
More specifically, with temperatures of 80°F, you can expect water levels to drop 0.25 inches a day. That would be considered normal, and you can add water every 7-10 days.
However at 105°F, you’re looking at losing an inch of water a day. That’s an additional 0.75 inches more per day than normal, so expect to add extra water every third day to make up for it.
Another major determinant of how much pool water you can lose to the environment is how humid it is. If you live in a coastal area that has high humidity, less water will evaporate such the air is already saturated.
If humidity were the only concern, living in a humid area may only cause the water to drop by 1 inch per month, as opposed to a more normal 1 inch per week. Generally speaking, the more humid the air is, the less often you need to add water to the pool, and the reverse is also true.
This factor ties in closely with humidity. If you live in a windy area, water will evaporate much faster than usual. Depending on how windy it is, the water level can decrease by 0.5 to 1 inch per day. This would require you to add water to the pool every other day.
Wind can also cause issues by blowing leaves, branches, and other debris into your pool. You will need to protect your pool by putting a cover over it, which is also a way for you to keep water from evaporating.
Not using a pool cover
By now, you should start to notice a pattern – that most of the water loss that occurs under normal circumstances is due to the weather. Heat, humidity, and wind can cause rapid loss of water, but only if your pool is exposed to them.
However, if you cover your pool with a pool cover, then there will be virtually no water loss on a day-to-day basis. You would then mostly be losing water during the periods where the pool is actually in use.
Frequency of use
The more often the pool gets used, the faster you will need to add water to it. This is because some water is bound to be splashed out, and swimsuits and hair will absorb water and remove it from the pool as people leave.
Also, you will obviously have to remove the pool cover so that the pool can be used, so the pool will once again be subject to the elements such as heat, wind, and humidity.
The amount of water lost varies depending on how long the pool was in use for, how many people were in the pool, and how much they were splashing around.
Children and teenagers are more likely to fool around and rough-house, causing water to be lost at a faster rate. You can expect the water level to drop by as much as 5 inches in one day. If the pool is used daily or multiple times a day, expect to add water back daily.
We’ve discussed various ways that the weather can remove water from the pool. However, as if to make up for the various ways water can be lost to the weather, rainfall can add fresh water back into the pool.
If you live in a place where rain is frequent and plentiful, you may never need to add water to your pool. In fact, you might even have to take some water out.
If you are aware of the other factors that can cause your pool to lose water rapidly, and are taking great care to have your pool covered up most of the time and to limit the amount of splashing that occurs when in use, and you find that you’re losing over an inch of water a day, then you may have a water leak.
Water can leak from any of the fittings (returns, lights, skimmers), cracks in the pool liner, a loose screw, a cracked pipe, and so on.
There are many reasons why your pool may be leaking, and many tests you can do to determine if your pool is leaking, where it is leaking, and how to fix it.
This topic goes beyond the scope of this article, this comprehensive guide covers how to detect and fix a leak in your pool.
Leaks are very serious. Even a small leak can cause you to lose an inch or more of water a day. If you suspect your pool has a leak, either fix it yourself or hire someone to fix it right away.
How can I tell if my pool is leaking?
A rudimentary test to determine if your pool is leaking is the bucket test (note: this test does not find out where it’s leaking, just that it is leaking).
Take a bucket and scoop some water from your pool. Place it near the pool so that it’s in the same environment. Now measure the water level of the water in the bucket and the water in the pool. Wait 24 hours.
After 24 hours have elapsed, measure how much the water in the bucket has decreased by, and measure the difference in the pool as well.
If the pool water level has decreased more than the bucket, that indicates that something beyond the weather is causing the water in the pool to be lost faster, and is usually indicative of a water leak. Just make sure your bucket isn’t also leaking for accurate results.
If the pool water level dropped as much as the bucket, then that means that there isn’t a water leak. However, clearly your environment is more hot, arid, or windy than you’d like, since it is causing your water to evaporate so quickly that you need to add water frequently.
Consider covering up your pool with a cover whenever it’s not in use. Also, if you have kids or teenagers using the pool often, tell them to be careful not to splash too much water out (hah, good luck with that).
You should only need to add water to the pool every 7-10 days, so if you’re doing it more often than that, then look over these factors and see which ones are affecting you.