When Does a Pool Need to Be Drained?
There are two main reasons a pool gets to the point where draining is the only real fix: the chemistry has gotten away from you, or the surface needs attention. Most of the time in Las Vegas, it's the chemistry — and it sneaks up faster than most people expect.
Water Chemistry — CYA and Calcium
Calcium hardness is the slow creep nobody talks about enough. Every time your pool loses water to evaporation, the calcium stays behind. Las Vegas pools lose 1–1.5 inches of water per day during peak summer — that's thousands of gallons a month just disappearing into the desert air. Every gallon you add back through the fill line brings in more calcium, because Las Vegas tap water already runs hard. Over time, calcium only goes one direction: up. Once it climbs past 600–800 ppm, you're fighting a losing battle with scaling, cloudy water, and equipment wear. The only real reset is a drain. Read more about calcium hardness in Las Vegas pools →
Cyanuric acid (CYA) is the other culprit. If your pool runs on trichlor tablets — which is most residential pools — every tablet adds a small amount of CYA to the water. CYA is a chlorine stabilizer, and in small amounts it's useful. Las Vegas UV is intense, which means pools burn through chlorine fast, which means more tablets, which means more CYA accumulating. Once CYA climbs above 80–100 ppm it starts binding to your chlorine and reducing how effective it actually is — called chlorine lock. You can have a chlorine reading of 5 ppm and still have a pool that won't sanitize properly. The fix isn't more chlorine. It's dilution, and that means draining.
Cosmetic Reasons to Drain
Chemistry aside, sometimes the pool just needs a surface reset. The tile line is one of the first places this shows up — calcium scale builds up at the waterline over time and is dramatically easier to clean on a drained pool. See our guide to bead blasting for tile cleaning →
Other situations where draining is the right call: metal staining from copper or iron in the fill water, mineral deposits embedded in the plaster surface, and cases where an acid wash is needed to remove organic staining or restore dull plaster. These aren't everyday items — but when they come up, the pool has to come down before any real surface work can happen.
How Do You Empty a Swimming Pool?
Draining a pool in Las Vegas isn't as simple as pulling a plug. The combination of extreme heat, expansive desert soil, and hydrostatic pressure can cause serious damage to a shell that's left empty too long. Here's how it's done correctly.
- 1Choose the right time
Never drain during peak summer heat if you can avoid it. Direct sun on exposed plaster causes rapid drying, cracking, and delamination. Early morning starts are best, and the pool should never sit empty overnight if temperatures are extreme. The goal is to drain, complete your work, and begin refilling the same day if at all possible.
- 2Set up a submersible pump
A submersible (trash) pump placed in the deep end is the most efficient way to empty a pool. Most residential pools take 8–14 hours to fully empty depending on size. Route the discharge hose to your sewer clean-out port — not to the street (see the municipal rules section below).
- 3Monitor as levels drop
Don't walk away. As the water level drops, the pump can run dry and burn out. Stay attentive as you get down to the last foot. Use a shop vac or squeegee to pull out the remaining water the pump can't reach in the shallow end and corners.
- 4Complete your work quickly
Whether it's an acid wash, tile cleaning, or surface repair — get it done fast. An empty pool in Las Vegas heat is a ticking clock on your plaster. Hydrostatic pressure from groundwater can also lift a shell if it sits empty too long, particularly following wet winters.
- 5Begin refilling immediately
Don't leave the pool empty any longer than necessary. As soon as the work is done, get water moving. We cover the refill process in detail in the section below.
Sewer Drain Rules by Municipality
While you don't need a permit to drain your pool in most Las Vegas jurisdictions, you should call your water provider to flag your account for high water use during the refill — this helps prevent excessive use charges (EUC) on your bill. Henderson requires this call specifically. Here's the contact information for each jurisdiction.
- 📞Customer Care: (702) 870-4194
- 🌐Pool Drain Guide — lvvwd.com
- 🕐Mon–Fri, regular business hours
- 📋No permit required. Call to flag account for pool refill water use.
- 📞Customer Service: (702) 668-8300
- 📧CustomerService@cleanwaterteam.com
- 🌐cleanwaterteam.com
- 🕐Mon–Thu 7:30am–4:30pm
- 📋No permit required. Pool water drains to sanitary sewer — contributing to wastewater treatment system.
- 📞Customer Care Center: (702) 267-5900
- 🌐cityofhenderson.com
- 🕐Mon–Thu 7:30am–5:30pm
- 📋Call before draining to flag your account — Henderson specifically requests this to prevent high-use billing flags.
- 📞Utilities: (702) 633-4200
- 🌐cityofnorthlasvegas.com
- 📋Drain to sewer lateral access port, sink, toilet, or bathtub only. Connect drainage hose to sewer clean-out pipe.
- 📞Non-emergency dispatch: (702) 293-9224
- 🌐bcnv.org/Public-Works
- 🕐Mon–Thu 7am–6pm
- 📋Contact Public Works to confirm your property's sewer connection before draining.
- 📞Septic Program: (702) 759-0660
- 📧septics@snhd.org
- 🌐SNHD Pool Drain Guide
- 📋Do NOT drain pool water into a septic tank — it will quickly overfill. Contact SNHD before draining for property-specific guidance.
How to Fill a Swimming Pool After Draining
Refilling a pool looks simple but has a few details that matter — especially if you want to avoid cosmetic damage to fresh plaster right from the start. See our full guide on managing pool water levels →
Most Las Vegas residential pools hold between 15,000 and 30,000 gallons. At a typical fill rate, expect 24–36 hours to reach full water level. Henderson requests you call (702) 267-5900 to flag your account before refilling so the extra water use doesn't trigger an excessive use charge (EUC) on your bill. Other jurisdictions recommend splitting the fill across two billing periods if timing allows.
- 1Never rest the hose fitting on bare plaster
A metal hose fitting resting on freshly drained plaster will leave an iron stain. Wrap the hose end so it never makes direct contact with the pool surface.
- 2Float the hose end
Tie a cluster of sealed, empty water bottles to the hose end with rubber bands or zip ties. The bottles float the hose end so it rises with the water level as the pool fills — staying submerged but never dragging across the plaster. Clean fill, no staining, no etching.
- 3Fill at a slow, steady rate — never pause
Stopping and restarting during the fill creates waterline rings on plaster — like a tide mark. They can be difficult to remove later. Better to leave on a slow trickle that runs continuously than to rush it in stages.
- 4Stay home while it fills
An overflowing pool is a flooded yard. Monitor the fill level periodically and don't leave the property for extended periods while the pool is taking on water.
What Order to Add Chemicals After Refilling
Fresh water in a freshly drained pool is a blank slate — but it's not ready to swim in. Chemistry needs to be dialed in from scratch, and the order you add chemicals matters more than most people realize. Some adjustments directly affect others, and adding things out of sequence causes cloudy water, wasted chemicals, and a week of chasing numbers.
See our full guide to LSI-based water balance → for a detailed explanation of how these variables interact — especially important in Las Vegas hard water.
- Total Alkalinity — establish the buffer first
- Calcium Hardness — structural chemistry for plaster protection
- pH — adjust after alkalinity is stable
- Cyanuric Acid — only if using a stabilized sanitizer system
- Sanitizer — chlorine or salt system startup
Need a Professional Drain & Cleanup?
We handle it safely — sewer-compliant, planned around the heat, done right the first time.
Keeping It From Happening Again
A drain and cleanup is a reset — not maintenance. The chemistry problems that lead to drains don't happen overnight. They're the result of small imbalances stacking up week after week — calcium creeping up, CYA accumulating, LSI drifting toward scale-forming. Consistent professional service catches these trends before they reach the drain threshold.
Our weekly pool service clients track water chemistry over time — calcium and CYA trends are monitored at every visit so problems are caught early. If your pool has already turned green and you're not sure whether you need a drain or a chemical treatment, see our green pool cleanup hub → For pools that can't wait, our emergency cleanup service → is available same-day.