Why Are There Maggots In Your Pool?


A group of maggots on the ground.

The only thing grosser than a fly problem is a maggot problem, especially when they are breeding in areas that you use to enjoy and relax, like a swimming pool. It can often be difficult to determine the source of maggots found in your pool because there are many factors at play that can be creating the perfect breeding ground. 

This article will look more closely at the potential causes for finding maggots in your swimming pool and some steps you can take to both remove them and prevent future infiltrations. Not only is swimming with larvae gross, but maggots, in particular, are commonly associated with feces and bacteria that can be dangerous when ingesting pool water that’s been around them. 

Maggots Crawl in From Nearby Plant Life and Garbage 

Houseflies often lay their eggs in areas that will offer enough nutrients and protection for growth. These hatches often occur on decaying organic matter and soon develop into fast-growing maggots (Source: How Stuff Works). Most commonly in your backyard, you may find maggots growing in your trash cans, yard waste, trees, or feces (such as dog poop on the lawn). 

When these areas are somewhat close to your pool, the larvae may make their way into the water. Maggots need to continue to grow where there are nutrients and prefer moist environments. This makes the swimming pool an attractive place for them to congregate if they can get there. If you have trees hanging over the pool or nearby, they can fall in. 

There are a couple of important precautions you can take to minimize the risks of maggots infesting your pool from an outside source: 

  • Clean your trash cans: Simply emptying your trash cans may not be enough to prevent the maggots from growing in your pool area. They may be able to grow in the remaining liquids and remnants at the bottom or find their way out of trash bags after emptying. Either way, you should be cleaning your trash cans regularly to get rid of or prevent them. You don’t necessarily need strong chemicals since hot and soapy water will eliminate the bacteria (Source: Plastic Place). You can also use vinegar, Lysol, or bleach.
  • Tend to trees: If larvae are going to be in trees, these are most like fruit-bearing where they can feed on nutrients. Often, they are attracted to rotting fruit, which usually results from neglected trees. Make sure you are tending to nearby trees and plants to prevent the decomposition of organic material. 
  • Yard waste and compost bins: You should also make sure to close compost areas that could attract flies for egg-laying. Lids should be tightly sealed on both compost and yard waste, at least until collection day for the latter. 
  • Pick up animal poop: Feces is one of the most common places for maggots to develop. Making sure to promptly pick up after dogs and other animals in the yard will prevent the development of larvae and keep them away from your pool. Be sure to check lawns and flowerbeds that are closest to the pool’s edge. 
  • Cover dog food: This also applies to human food being left outside, but dog food bowls should be covered and completely emptied after use. Idle food is a great place for flies to lay their eggs (Source: Warwick District Council). 

You must address these issues in the summer months when the temperature is warmer and more likely to be humid. Maggots thrive in these environments, and when coupled with one of the previously-stated issues, they can successfully exit the larvae stage, grow, and multiply. 

Making sure none of these factors occur makes it much easier to identify why there may be maggots in your pool. It would help if you also made these necessary changes to keep areas of your backyard healthier and cleaner. 

Imbalances in Chemicals and Water pH Offer Breeding Grounds

Once the other easier items have been addressed, you may have to make changes to the chemicals in your pool and perform tests to see if the water is the cause of your maggot problem. There are multiple levels and areas of the pool you should be looking at to ensure that the chemical composition will not allow for larvae to live comfortably. 

To provide a clean and safe pool environment, these are the following levels you should keep for chemicals: 

  • pH levels: Maintaining pH levels of 7.4 to 7.6 is important for the balances of chemicals in the pool. It is especially important for making sure that chlorine can do its job (Source: SwimmingPools.com). When the pH is too basic (high alkaline), it cannot kill the bacteria and pathogens it needs, too. When the water is too acidic, the chlorine goes away too quickly and needs to be replenished. 
  • Chlorine: The ideal amount of chlorine in your pool should be 1–3 ppm. This needs to be checked regularly in addition to pH to make sure both are maintaining their necessary levels (Source: Ultimate Pool Care). 
  • Alkalinity: Beyond pH, you can also measure the total alkalinity. This looks more closely at the total amount of alkaline substances in the water as opposed to a balance of pH. 80-140 ppm is the necessary level for helping keep the pH balance. 
  • Calcium hardness: Keeping the hardness of pool water at 200-400 will help to prevent corrosion and issues with pH and chlorine. 

All of these levels must be maintained to make sure that chlorine can do its job. If you find maggots in your pool, it may be likely that your chemical levels are not within their ideal range. You should use a pool testing kit and then make changes according to the imbalanced categories. 

How to Clean and Remove Maggots from Your Pool 

Once you have identified that the chemical levels must be changed, you need to address the immediate problem. Removing maggots from the pool must coincide with chemical additions to prevent rebreeding. 

Take the following steps to remove maggots from the pool: 

  1. Check pool filter: You may find that the larvae are congregating in the pool filter because it is a dark space that can catch decomposing organic matter. You should regularly check the filter to ensure that dead animals and larger plant material have not become trapped. 
  2. Net the maggots out: Remove all maggots from the pool with a pool net. They should be deposited in the trash, but first, they need to be killed. Submerge them in boiling water and use baking soda or bleach to kill them. Make sure they are properly put into a trash bag so that they can be taken on collection day. 
  3. Shock the pool: Because it can be difficult to know if you have gotten them all, you should shock the pool or add additional chlorine to eliminate these pathogens and bacteria. You can use either liquid or granular chlorine to address the maggots (Source: Dengarden). Using granular chlorine or calcium hypochlorite is best for stronger applications to ensure that the larvae are killed. 
  4. Maintain chemical levels: You should be checking the chemical levels regularly after shocking the pool. This should be completed about a week after the shock as the chlorine levels drop. 

In Conclusion 

The main causes of the maggots in your pool are the low chlorine levels that could be allowing for bacteria growth. This creates an ideal environment for the larvae to live and reproduce. If you are keeping these levels in check, consider the outside factors in your yard that may be attracting the maggots into your pool. 

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