This final installment of our series (see Part 1 & Part 2) focuses on some practical considerations when water actually needs to be removed from an inground swimming pool.
As we’ve discussed throughout this series, completely draining an inground pool isn’t routine maintenance. Depending on the pool’s construction and groundwater conditions, removing the weight of the water can expose the pool to forces that may damage the shell, surface or liner. Before completely emptying a pool, make sure draining is actually necessary and that you understand the requirements for your particular pool.
Use the Right Equipment for the Job
How water should be removed depends on the pool, its plumbing and equipment, how much water needs to be replaced and why you’re draining it.
A partial water replacement may be all that’s necessary for some water-chemistry issues. Major repairs or renovations, on the other hand, may require the water level to be lowered considerably or the pool to be completely emptied.
Pool pumps and filtration systems also aren’t all configured the same way. Don’t assume that a particular valve position, filter setting or plumbing arrangement described online applies to your equipment. Operating a pump without adequate water flow can damage it, and modifying pool plumbing simply to drain the remaining water introduces another opportunity for leaks or equipment problems.
Submersible pumps are commonly used when substantial amounts of water need to be removed independently of the pool’s normal circulation system. Larger pumping equipment may sometimes be used by pool professionals for major projects, but faster isn’t necessarily better. The discharge location must be able to handle the flow without causing flooding, erosion or other problems.
If the pool contains heavy debris, contaminated water or large amounts of algae, disposal requirements may also be different from those for ordinary pool water.
Don’t Drain More Water Than Necessary
Before completely emptying a pool, determine whether the work actually requires it. If you’re replacing water to address a water-chemistry issue, a partial drain and refill may sometimes accomplish the goal without exposing the pool to the additional risks associated with being completely empty.
The same principle applies to certain repairs. If lowering the water below the area being serviced is sufficient, there may be no reason to remove every gallon.
When a complete drain really is required, have the repair, resurfacing or other work planned before you begin. Gather the necessary materials, schedule contractors if they’re involved and make sure everyone understands the timeline. An inground pool generally shouldn’t remain empty longer than necessary.
Choose the Right Time to Drain a Pool
Weather and groundwater conditions deserve serious consideration before an inground pool is completely drained. Heavy rain can raise groundwater levels, increasing the pressure outside and beneath the pool. If you don’t know the groundwater conditions around your pool, don’t simply assume that the ground is dry enough because it hasn’t rained that particular day.
The pool’s construction matters as well. As we discussed in Part 2, concrete, fiberglass and vinyl-liner pools have different concerns when their water is removed. Manufacturer instructions should be followed when they apply, particularly with fiberglass and vinyl-liner pools.
Weather can also affect exposed pool surfaces and materials. Instead of relying on a universal outdoor-temperature cutoff, follow the recommendations for your particular pool surface, liner and repair procedure. Direct sunlight and high temperatures can also be concerns for some exposed finishes and liners, so “warmer is always better” isn’t a good rule either.
If you’re completely draining the pool for a repair or renovation, choose a period of suitable weather and be prepared to complete the work and refill the pool without unnecessary delays.
Know Where the Pool Water Is Allowed to Go
Thousands of gallons of pool water have to go somewhere, and choosing the discharge location isn’t simply a matter of finding an empty section of your yard.
Rules for disposing of swimming pool water vary by state and municipality. Depending on where you live, local authorities may specify whether pool water can be discharged onto your property, into a sanitary sewer or through another approved method. There may also be requirements involving chlorine or other pool chemicals before the water can be released.
Don’t assume that a nearby storm drain is an acceptable destination. Stormwater systems frequently discharge into streams, rivers and other bodies of water without the treatment provided by a sanitary sewer system. Chlorine, salt, algaecides and other substances in pool water can create environmental concerns, and local rules may prohibit or restrict that type of discharge.
Before draining a substantial amount of pool water, check with your local water, sewer or environmental authority to determine what is permitted where you live.
If discharge onto your property is allowed, the water should be released at a rate and location that won’t flood neighboring property, erode soil, damage landscaping or simply soak back into the ground immediately around the pool. This last concern is particularly important when you’re trying to avoid increasing groundwater pressure around an empty inground pool.
Don’t Turn Pool Draining Into a Race
The original temptation may be to get the water out as quickly as possible, especially when you’re eager to begin a repair. But the fastest pump available isn’t necessarily the best approach.
The discharge system and destination need to accommodate the flow, and you should remain aware of changing weather, groundwater and pool conditions while the water level is dropping. If something unexpected happens, stop and determine what’s going on rather than continuing simply because the pump is already running.
Once the required work is finished, refill the pool according to the recommendations for its construction and finish. Vinyl liners and certain other pool components may require particular procedures as the water level rises, while newly applied pool finishes can have their own startup requirements.
If you’re uncertain about any part of completely draining an inground swimming pool, call an experienced pool professional before you start. That’s particularly important with fiberglass pools, older vinyl liners, high groundwater, recent heavy rainfall or a pool that needs structural or surface repairs.
Draining a swimming pool isn’t necessarily complicated in every situation, but the consequences of getting it wrong can be considerably more complicated than the job you were originally trying to accomplish.
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