When a pool is winterized properly, it is much easier to reopen when swimming season resumes. It is especially important that you don't remove the pool cover until the area around the pool has been cleaned, which can be done by sweeping or hosing away the debris. This will prevent it from falling into the pool. Next, fill the pool to its normal water level using a garden hose. Anything that was disconnected for winter will need to be reconnected now. Open the skimmer line valve to allow water to flow through the circulation system. Finally, test the water’s pH level and shock the pool. The pool will take a week or more before it will become swimmable and balanced. Until the water is balanced, leave the pump running 24 hours a day and reduce the run each day by only one to two hours.
If it often difficult to decide if low water levels in your pool are due to a leak or evaporation. A simple bucket test can help you discover leaks in your pool. Fill a plastic bucket three-quarters full of water. If it has a handle, remove it, which allows for better stability in the water for the bucket. Mark the water line on the inside of the bucket. Place it on a step in the pool, and mark the water line on the outside of the bucket as well. Let the bucket sit in the pool for two to three days. At the end of the test, if the water levels on the inside and outside have gone down the same amount, evaporation is causing your pool levels to dip. However, if the water level on the outside has gone down quicker than the water level inside the bucket, your pool has a leak. Now you need to call a professional to have the leak fixed.
Over time organic contaminants like nitrogen or ammonia build up in a pool. Very high levels of such contaminants can interact with a pool's chlorine to form chloramines. The potent chlorine smell that many people associate with pools is a result of this interaction. To remove this harsh odor, the pool water must be superchlorinated or shocked back to normal chlorine levels. While it seems illogical, the undesired odor goes away when a large amount of chlorine is added to the pool. While some pools need to be shocked once a week, others can wait much longer between the services. To get the best results, follow manufacturers’ instructions before superchlorinating your pool.
To make sure pool water is clean and healthy, it should be tested regularly. The pH scale is a measurement of alkalinity or acidity that runs from 0 to 14. The ideal reading is between 7.2 and 7.8, which helps sanitizers work at top efficiency and is safe for swimmers.

A testing kit will allow you to monitor your pool's pH level. There are a variety of different kinds of testing kits available; however, most versions for homeowners are either test-strips or reagent kits. For the reagent kits, you take a sample of pool water and add liquids or tablets to it. The water will then change color, indicating its chemical balance. For test-strip kits, you submerge the strip in the pool for a few seconds; it will change color due to the dyes it contains. Next, to determine the pool’s pH level, match up the strip to a color chart. Then use this information to determine what kind and how much of the chemicals your pool needs.

Throughout the swimming season, a lot of water will be lost largely because of evaporation and normal wear and tear, such as splashing, swimming, and exiting the pool. A good time to check the water level is when you remove debris with your skimmer throughout the week. The pump could be damaged if the water level falls below the level of the skimmer. If the water level is low, use a garden hose to bring it back up to a safe level for the skimmer/pump.

If you drain your pool once the swimming season has passed or to perform maintenance, do not let the pool sit empty for too long. In general, throughout the winter it's best to leave water in a pool because the weight of the water counteracts the forces from the ground pressing up against the pool’s bottom.

Pool heaters usually require the least maintenance of all pool equipment. Without being serviced for a couple years, gas heaters can work fine; and electric ones can last even longer. For specific care instructions, consult your manufacturer's manual. However, calcium scales can build up inside the tubes of a heater and restrict flow, which prevents the water from heating adequately. If you suspect this is an issue with your heater, recruit the help of a professional. The heater may need to be disassembled and have its tubes cleaned out with acid or a wire brush.