Introduction: The Impact of Rain on Your Pool
After a heavy rainstorm, you may notice your swimming pool water level rising far beyond the recommended range. While rainwater can seem like a natural way to sustain your pool’s water level, excessive water introduces a host of challenges — from skimmer inefficiency to imbalance in pool chemistry. Knowing how to lower the water level in your pool after it rains is crucial for maintaining a clean, safe, and operational swimming environment.
In this article, we’ll take a thorough look at the reasons for lowering pool water after rainfall, practical methods to remove excess water, tools you’ll need, and preventative measures to reduce future water level fluctuations. Whether you’re a long-time pool owner or new to the maintenance game, this guide will equip you with the knowledge to manage your pool effectively, no matter the weather.
Why Pool Water Level Matters
Optimal Pool Water Level and Operation
Maintaining a proper water level in your pool is key to the efficient functioning of the entire system. Most pools are designed so the skimmer operates optimally when the water level is between one-third and halfway up the skimmer opening. If the water level is too high:
- The skimmer may not operate effectively, allowing debris to remain in the pool and increasing filter work.
- Water circulation is affected, which leads to uneven chemical distribution and the formation of stagnant zones.
- The efficiency of automatic pool cleaners can be reduced if the water level interferes with their float mechanisms.
Additionally, water that’s excessively high can spill over and cause damage to the surrounding deck or pool equipment, especially if it leaks into sensitive electrical systems.
Chemical Balance Maintenance
Rainwater is untreated and unregulated — it lacks chlorine, pH balancers, and other chemicals that keep your pool water safe. When rainwater mixes with your pool water, it dilutes the chemical balance, potentially leading to algae growth, cloudy water, or unsanitary swimming conditions.
Methods to Lower Your Pool Water Level After Rain
When your pool has absorbed more rainwater than desirable, consider the following practical and safe methods for reducing the water level effectively.
Method 1: Using a Submersible Pump
A submersible pump is one of the most effective ways to remove water from your pool efficiently. These pumps are specifically designed to work underwater and operate quietly and safely.
Steps:
- Choose a pump with appropriate horsepower — a 1/4 HP unit is ideal for smaller pools or light rain events, while larger pools may need a 1/2 HP pump or more.
- Place the pump at the deep end of the pool.
- Attach a garden hose to the pump, and ensure it’s routed to a safe drainage area — a landscaped area, storm drain, or dry well.
- Plug in the pump and monitor the water level as it lowers over time.
Make sure not to empty the pool completely, as it can cause structural issues. Pools are designed to hold water, and draining them completely during hot weather can lead to cracks or shifting.
Method 2: Using the Pool Filter in Waste Mode (for Sand and DE Filters)
If your pool uses a sand filter or a diatomaceous earth (DE) filter, you can drain the water directly using the “waste” setting on the multiport valve. This method allows you to bypass the filter entirely and send water straight to waste.
How to Operate Waste Mode:
| Step | Action |
|---|---|
| 1. | Turn off the pump. |
| 2. | Set the multiport valve to “waste.” |
| 3. | Turn the pump back on and allow it to run until the desired water level is achieved. |
| 4. | Turn off the pump and reset the valve to “filter” position. |
Note: This method is only possible with certain filter types. Cartridge filters don’t have a “waste” setting — attempting to use one this way may damage the filter or cartridge.
Method 3: Using a Siphon System
A manual siphon system involves using a hose and gravity to help lower the water level. While slower than the submersible pump method, a siphon is an effective, equipment-free process if you’re not dealing with a huge volume of water.
Steps:
- Place one end of the garden hose in the pool.
- Submerge the hose completely to fill it with water.
- Place the other end of the hose lower than the pool water level, preferably on a slope or in a drainage area.
- Once primed, water will begin siphoning out of the pool.
Ensure the hose won’t kink or raise above the pool level during operation, and regularly check for flow. This method is best suited for small to moderate overflows.
Method 4: Professional Assistance
If your pool is consistently overwhelmed by rainwater due to improper installation, lack of overflow drains, or proximity to low areas that channel water toward the pool, it might be time to call in a professional.
Licensed pool contractors can:
- Install an automatic pool water level control system.
- Set up permanent drainage infrastructure, including overflow drains or underground drainage lines.
- Determine if your pool has structural vulnerabilities that exacerbate flooding problems.
They can also address issues with your filtration and chemical systems post-rain to restore proper operation and safety.
Special Considerations: Above Ground vs. Inground Pools
The method of lowering water depends partly on your type of pool. Let’s examine the differences:
Lowering Water in Inground Pools
Inground pools often have multiport valves for filters (sand/DE) which make it easy to remove water quickly. In addition, many use submersible pumps that can efficiently drop the level as needed. Because of their construction and design, they’re better suited for handling excess water temporarily without long-term issues.
However: Inground pools should never be drained below 18 inches of the bottom to avoid hydrostatic pressure issues — where groundwater can push the empty pool out of the ground, a phenomenon known as “floating.”
Lowering Water in Above Ground Pools
Above ground pools are more sensitive to improper emptying. They rely on the pressure and weight of the water to stabilize their structure.
Important: Do not use the waste line method if you have a cartridge filter system, and never drain the water below the return jets to prevent structural damage.
Additionally, siphoning with a garden hose or using a small portable pump is typically sufficient after a rainfall for these pools.
What to Do After Draining Excess Water
Draining too much water can unbalance your pool system just as much as leaving it too high. After restoring the proper water level, the next priorities involve maintaining clarity, chemistry, and system operation.
Check Chemical Levels
Heavy rainwater dilutes chlorine, pH, alkalinity, and calcium levels. After reducing your water level:
- Test your pool water using pool test strips or a liquid test kit.
- Adjust the free chlorine levels to between 1–3 ppm (parts per million).
- Ensure a pH level between 7.2 and 7.8 for swimmer comfort and effective chlorine action.
- Use shock treatment if needed to destroy organic contaminants from rainfall.
Clean the Pool
Rainwater often brings leaves, dirt, and other organic matter into the pool. Scrub the pool walls and floor, and run your filters for longer cycles (up to 12–24 hours) to clear any cloudiness.
Inspect Pool Equipment
Rain can cause water to reach areas where it normally doesn’t belong, especially if water overflowed. Check:
- Pump motor housing for water intrusion.
- Electrical components near the pool for moisture or short circuit signs.
- Skimmer lid and pump strainer basket for debris buildup or waterlogging.
Backwash and Clean Filters
After draining and filtering rainwater, your filter will likely need a backwash to remove excess debris picked up during the storm. For cartridge filters, simply remove, rinse, and reinsert the elements.
Prevention: Minimizing Water Overload During Future Rainfall
A proactive strategy can minimize the impact of heavy rain and make future cleanups easier.
Install an Overflow Drain or Gutter System
Some pools, especially commercial or larger residential installations, feature overflow gutters or perimeter drains. Installing such a system:
- Keeps water level stabilized
- Redirects excess rainwater safely to a drainage system
- Can also serve aesthetic architectural purposes
This is more of a permanent solution that is best discussed with a pool contractor.
Keep the Pool Water Level Consistent
Monitoring and maintaining a slightly lower water level throughout the rainy season can provide a buffer — a level at or slightly below halfway in your skimmer is optimal to allow for water gain.
This proactive management is especially crucial in areas with frequent or prolonged rainy seasons.
Clear the Skimmer of Debris Regularly
Clogged skimmers reduce water intake and are more likely to overflow during rains. Clearing debris from the skimmer regularly ensures proper operation during high-volume periods.
Adjust Automatic Water Fillers
If you have an automatic pool water leveler or autofill system, you can adjust the float setting to maintain a slightly lower water level. This keeps plenty of headspace before heavy rains.
Environmental and Legal Considerations
When you drain pool water, you are responsible for handling it responsibly. Pool water is considered non-potable and often contains chlorine, algaecides, and other chemicals.
Do Not Drain into Storm Drains Without Proper Treatment
The release of chlorinated water directly into storm drain systems, surface waters, or public waterways is often regulated by local municipalities and environmental agencies.
Before discharging pool water outdoors:
- Test chlorine levels — stop discharging until levels are below 0.1 ppm.
- Use dechlorination tablets or solutions to neutralize residual chlorine.
- Use a multi-media filter or carbon filter to remove suspended solids and chemicals.
Redirect Water Away from Sensitive Areas
Ensure drainage is going into legal, environmentally responsible areas. Don’t discharge into:
- City sewers unless your system is permitted for that use
- Near plant beds or vegetable gardens — chlorine can damage or kill sensitive plants
- Areas close to wells, reservoirs, or neighbors’ yards
Pool Design Solutions for Water Level Stability
Modern pool construction and renovation offer options to help manage water level stability across seasonal climatic changes.
Automatic Water Level Control Systems
These systems continuously monitor the water level, using a combination of sensors and a pump or valve to maintain it within a specific range. They are excellent for high-rainfall areas or pools with frequent or automatic chemical dosers.
Spa-Only Overflows
In pool/spa combo installations, spas often have a built-in overflow line that can be connected to a drainage system. This diverts excess rainwater before it reaches the main pool, improving integrated management.
Deck Grading and Drainage Enhancements
Ensuring that the area surrounding your pool is graded to divert rainwater away rather than into the pool is a smart landscape engineering solution. Installing surface drains along edges or nearby patios also helps.
Troubleshooting Common Issues After Heavy Rainfall
Even with the best maintenance, certain difficulties can arise following heavy rain.
Cloudy or Green Water
Rainwater can introduce nutrients and organic debris that feed algae. If your water turns cloudy or green, it’s likely due to an algae bloom or chemical imbalance.
Solution: Add a chlorine shock, clean the filter, and run the pump continuously until water clears. Algaecide can also help.
High Water Level Despite Efforts
Recurring high water levels can indicate poor water management or improper filtration. Ensure the waste line is open during draining, or the pump is functioning properly. If necessary, consult a technician to test your system’s efficiency.
Hydrostatic Valve Issues in Inground Pools
If you suspect your inground pool hydrostatic valve is failing, this can result in the pool “floating” or cracking from excessive groundwater pressure. Signs include bulges or cracks in pool walls or a valve that no longer allows balanced pressure.
Prevention Tip: If your water level keeps going up without rain, have the valve inspected by a licensed pool technician.
Conclusion: Managing Pool Water Levels After Rain
Maintaining balance in your pool is just as important during heavy rainfall as the rest of the year. Knowing how to lower the water level in your pool after it rains is an essential skill that will keep your pool clean, chemically balanced, and visually appealing year-round.
By using submersible pumps, managing multiport valves effectively, and investing in preventive infrastructure, every pool owner can ensure their system operates at peak performance regardless of weather conditions. Furthermore, taking the time to monitor and adjust chemical levels after a storm will provide a safer swimming environment and reduce the chances of persistent issues like algae growth or mechanical damage.
Whether you take a hands-on approach or work with pool professionals to optimize your drainage structure, having a reliable strategy post-rainfall is crucial for long-term pool ownership success.
Remember: proactive steps like adjusting automatic fillers, installing overflow drains, and designing effective surrounding drainage can reduce the frequency of needing to lower your pool water manually. Stay ahead of the rain, and your pool will always be ready for action.
Why does the water level in my pool rise after it rains?
Rainfall directly adds water to your pool, especially if it’s uncovered. If your area experiences heavy or prolonged rain, the water level can rise significantly, potentially leading to issues like poor filtration, overflow, and chemical imbalance. Pools located in low-lying areas or with poor drainage around the perimeter are particularly prone to this problem.
To prevent long-term damage, it’s important to monitor the pool’s water level after rainfall and take steps to bring it back to the recommended level. Regularly checking surrounding drainage systems and considering preventive measures like installing pool covers or improving yard grading can help reduce the frequency and severity of high water levels.
What is the ideal water level for my pool?
The ideal water level for most in-ground pools is at the midpoint of the skimmer opening. This ensures proper skimming action, which helps keep the surface clean and allows the pump to function efficiently. For above-ground pools, the water level should be about 1–2 inches below the rim of the pool wall to prevent spillage and maintain good functionality.
Maintaining the correct water level also helps protect pool equipment. Water levels that are too high can interfere with the skimmer’s operation, reduce filtration efficiency, and even cause the pump to lose prime. When levels are too low, the pump can intake air, leading to overheating or damage. Keeping the water at the recommended level makes pool maintenance easier and more effective.
Can I use the pool pump to lower the water level?
Yes, you can use your pool pump to lower the water level, but it requires careful monitoring. Set the pump’s filter valve to the “drain” setting, which allows water to be expelled from the pool through the waste line instead of being recirculated. Make sure the waste line is directed to a safe drainage area away from your home’s foundation or landscaping.
While using the pool pump is effective, it should only be done temporarily since extended use in the drain setting can cause the pump to run dry if the water level drops below the skimmer. Additionally, using the pump to drain large volumes of water may be inefficient and place unnecessary strain on the system. It’s best suited for minor water level adjustments.
What is a submersible pump, and how does it help lower the water level?
A submersible pump is a portable, electric pump designed to sit inside the pool or water source and pump excess water directly out through a hose. These pumps are highly effective for quick and efficient water removal, especially after heavy rain, and are available in various sizes depending on the volume of water you need to remove.
Submersible pumps are particularly useful because they can remove water below the level of the skimmer, which is often left behind when using the pool pump. They’re relatively easy to set up and operate, but it’s important to follow safety precautions, such as using a ground fault circuit interrupter (GFCI) outlet and ensuring the pump remains submerged during operation to avoid overheating.
How can I manually remove water from my pool without a pump?
If you don’t have access to a pump, you can manually remove water using a pool siphon hose or a manual bilge pump for smaller pools or spas. Start by filling the hose with water using a garden hose to create a vacuum, then place one end in the pool and the other at a lower elevation to start gravity-based drainage. This method takes time and is best for smaller water level reductions.
Alternatively, a manual bilge pump — commonly used in boats — can help remove water from the pool’s deep end. Though labor-intensive, this method can be useful in emergencies or for small amounts of water. For larger pools or heavy rainfall, however, using a power pump is usually more practical and time-efficient.
Should I adjust the chemicals after lowering the water level?
Yes, lowering the water level after rain can affect your pool’s chemical balance. Rainwater often contains contaminants and may dilute existing pool chemicals, reducing their effectiveness. This can lead to algae growth, cloudy water, and potential scaling or staining of pool surfaces due to shifts in pH and alkalinity.
After adjusting the water level, it’s essential to test the water using a reliable test kit or strips, and then rebalance the chemicals to ensure they’re within the recommended ranges. Pay particular attention to chlorine, pH, alkalinity, and calcium hardness. This step is crucial to maintaining clean, safe water that’s comfortable for swimming and protective of your pool’s equipment and surfaces.
How can I prevent the water level from rising too much during future rainstorms?
To help prevent excessive water accumulation, consider using a snug-fitting pool cover during heavy rain or storms. Pool covers act as a barrier to rainwater, significantly reducing the amount that enters your pool. Additionally, ensuring proper yard drainage around your pool area can help redirect water away from the pool’s edge.
Installing a water leveler or automatic pool drain can also help manage water levels more efficiently by automatically releasing excess water. Another important step is inspecting and maintaining nearby gutters, downspouts, and French drains to ensure they’re functioning properly. Taking these preventive steps not only protects your pool but also reduces the labor and cost of frequent water removal after heavy rains.