Why Draining Your Inground Swimming Pool Could Be Dangerous

Child sits with rubber ring by empty pool
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A reader asks: I'm attempting to drain my inground plaster swimming pool for the first time, to do some plaster repairs. I have never drained it before. I'm setting the pump to backwash and letting it drain, but when the swimming pool water level goes below the skimmers it stops pumping. I guess it's sucking air from the skimmers. I have two valves to shut off skimmers, but if I do that it won't drain the swimming pool, right? I don't know how to shut off the skimmers without shutting the main drain at the bottom of the swimming pool. Do you have any advice? This is my first pool and I don't know that much about swimming pools.

Draining a pool is probably one of the biggest mistakes a homeowner can make because it is extremely dangerous.

Cases When You Might Drain a Swimming Pool

There are only very few times one need to ever drain a swimming pool.

  • To dilute the Total Dissolved Solids (TDS) or even stabilizer. These typically only require a partial draining.
  • If you have a repair to be made, this can be a reason to drain a pool.
  • For most cleaning, even when your pool looks like a toxic waste dump, you should not drain the pool.
  • In this case described above, the pool builder did a good thing. He tied the skimmer into the drain to keep you from accidentally draining the pool, and it worked.

Why Draining a Pool Is Dangerous

When one drains the pool and there happens to be water under the shell (like in the rainy spring when people want to clean up the pool) the entire pool shell can heave. This is because the water under the pool creates an upward hydrostatic force (through buoyancy) and the pool is lifted out of the ground.

Contact a local pool service company and pay them to come out and open your pool for the very first time. You can also get a pool guide by creative homeowner's that covers the basics. If you have any other specific questions, please don't hesitate to ask.

Tips for Finding the Right Pool Company

Okay, you have decided to consult the pros and leave the pool-draining to the experts. Now you have to find the best one. If you wait until pool season is in full swing, expect some delays, especially if you are a new client to the pool service company. Before you call to schedule an appointment, consider these tips.

  • Read reviews online. Spread your research across multiple review sites.
  • Call or make an impromptu visit to the store or the business. The way they treat you when you show up says a lot about what you can expect as a customer.
  • Ask your friends and family members for recommendations.
  • Visit the Association of Pool and Spa Professionals site for recommendations and a list of association members. Look for the APSP logo on the door of the pool professional;s establishment, or inquire about membership on the phone. While membership to the association is not a requirement, it does help you find reputable professionals who meet APSP guidelines. APSP certifications include: CBP Building Service Pro,  CSP Certified Service Pro, CSP Certified Service Tech, CMS Certified Maintenance Specialist, CHTT Certified Hot Tub Technician.
  • Ask about insurance coverage. Do not do business with any company, especially swimming pool and hot tub professionals, that cannot provide you with proof of adequate insurance coverage. You don't want anyone to walk onto your property without the proper coverage to protect themselves and your pool.
  • Ask about warranties, service warranties, and any other protections offered by the pool company specifically or the manufacturers they work with that furnishes the equipment for your pool.