How Much Does It Cost to Drain a Pool?
Draining a swimming pool is a major maintenance procedure required every three to seven years when water accumulates excessive Total Dissolved Solids (TDS), high cyanuric acid (CYA) stabilizer levels, or when undertaking structural plaster replastering, acid washing, or tile repairs. However, emptying 15,000 to 30,000 gallons of water is not as simple as flipping a valve on your pool filtration equipment. Draining a pool carries severe structural risks—most critically hydrostatic pressure from underground water tables that can physically float an inground pool out of the ground or cause vinyl liners to shrink and tear. The cost to drain a swimming pool varies based on whether you rent a submersible pump to execute a DIY drain or hire a professional pool service company. On average, draining a pool costs between $175 and $400 for professional labor, plus $60 to $250 in municipal water utility fees to refill the pool.
DIY Submersible Pump Rental vs Professional Pool Service Costs
Homeowners seeking an economical approach can drain a pool independently using a rented commercial submersible utility trash pump. Pool professionals strictly advise against using your pool's existing centrifugal circulation pump to drain the pool below the bottom skimmer mouth, as running air into the suction line will burn out the pump motor and mechanical shaft seal. Renting a 2-inch or 3-inch submersible electric trash pump and 100 feet of discharge lay-flat hose from a local equipment rental center (like Home Depot or Sunbelt Rentals) typically costs $40 to $70 for four hours, or $60 to $100 for a full 24-hour day.
In contrast, hiring a professional pool maintenance technician provides complete peace of mind and safeguards against structural catastrophe. A professional pool service charges between $175 and $400 to drain a residential pool. This turnkey service includes deploying industrial submersible pumps, routing discharge water legally into designated municipal sanitary sewer cleanouts, monitoring the drain continuously, opening bottom hydrostatic relief valves in plaster floors, and inspecting structural surfaces as the water line recedes.
The breakdown table below contrasts costs, equipment requirements, and liability risks between DIY pump rentals and professional pool draining services.
| Draining Approach | Equipment Utilized | Labor / Service Cost | Structural Pop-Out Risk & Liability |
|---|---|---|---|
| DIY Submersible Pump Rental | Rented 2" electric submersible pump | $50 to $100 (Rental fee) | High risk (Homeowner assumes full liability) |
| Professional Pool Service Drain | Commercial high-flow trash pumps | $175 to $400 | Low risk (Insured technician monitors relief valves) |
| Drain & Chemical Acid Wash Package | Submersible pump + muriatic acid scrub | $500 to $950 | Removes stubborn algae & mineral plaster stains |
| Drain & Chlorine Bath Shock | Pump + concentrated sodium hypochlorite | $350 to $650 | Eliminates severe black and green swamp algae |
Draining an average 20,000-gallon inground pool typically requires 8 to 14 hours depending on pump discharge gallons-per-minute (GPM) ratings.
Hydrostatic Pressure Relief Valves, Shell Pop Risks, and Refill Utility Costs
The single most dangerous hazard when draining an inground concrete (gunite/shotcrete) or fiberglass pool is hydrostatic water pressure. When a pool is full, 20,000 gallons of water exerts approximately 166,000 pounds (over 80 tons) of downward gravitational ballast, holding the concrete shell firmly in the earth. If the surrounding water table is elevated due to recent seasonal rainfall, groundwater pushes upward against the empty, buoyant concrete shell. Without downward ballast, the pool can literally 'pop' several feet out of the ground, rupturing underground plumbing and cracking the concrete shell beyond repair.
To prevent structural floating, technicians open the hydrostatic relief valve located inside the main bottom drain pot as soon as the water level drops to the deep end floor, allowing groundwater to enter the pool rather than pushing beneath it. Once maintenance is finished, the pool must be refilled immediately. Refilling a 20,000-gallon pool using residential garden hoses takes 24 to 40 hours and adds $80 to $220 to your municipal city water utility bill. Purchasing clean bulk water delivered via commercial tanker trucks ($300 to $500 per 6,000-gallon tanker) costs between $1,000 and $1,600 total.
The reference table below outlines municipal water refill expenses and chemical startup costs following a complete pool drain.
| Refilling / Startup Expense | Method / Provider | Typical Cost (20,000 Gallon Pool) | Time to Complete |
|---|---|---|---|
| City Municipal Water Hose Refill | Home outdoor hose spigots | $80 to $220 (Utility bill) | 24 to 36 Hours continuous run |
| Commercial Bulk Tanker Water | Potable water delivery trucks | $1,000 to $1,600 (3-4 trucks) | 2 to 3 Hours rapid fill |
| Chemical Startup Balancing Kit | Cyanuric acid, shock, pH, calcium | $100 to $200 | 1 to 2 Days chemical cycling |
| Hydrostatic Relief Valve Replacement | New brass/threaded O-ring valve | $25 to $50 part + labor | Installed before refilling |
Call your city water utility before refilling; many municipalities will waive the accompanying sewer charge on pool refills upon request.
How to Safely Drain an Inground Pool in 4 Steps
Follow these four essential safety steps to monitor groundwater, rent proper pumps, and prevent structural pool damage.
Check Local Groundwater Levels and Weather Forecasts
Never drain a pool during rainy seasons or when the water table is high. Inspect your yard's groundwater inspection well pipe if available.
Discharge Water Legally into Municipal Cleanout
Locate your home's dedicated sanitary sewer cleanout port and route the pump discharge hose directly into it, avoiding street storm drains.
Submerge Pump in Deep End and Monitor Drainage
Lower an electric submersible pump into the deepest point of the pool, plug into a GFCI outlet, and monitor the water drop continuously.
Unscrew Bottom Hydrostatic Relief Plug
As the deep end empties, remove the main drain cover and unscrew the hydrostatic relief plug using channel lock pliers to equalize groundwater pressure.
Frequently Asked Questions (8 Questions Answered)
Q1: Can draining a pool ruin it?
Yes. If the surrounding groundwater table is high, an empty inground concrete or fiberglass pool can pop out of the ground like a boat, destroying the structure and plumbing.
Q2: Can I drain my pool using my pool's own pump?
No. Pool filtration pumps lose prime and suck air once the water level drops below the skimmer, overheating the impeller and burning out the motor within minutes.
Q3: Where are you legally allowed to drain pool water?
Most municipal environmental codes require pool water to be discharged into your home's private sanitary sewer cleanout, strictly prohibiting draining chlorinated water into storm drains.
Q4: How long can a pool stay empty?
Keep a pool empty for the absolute minimum time necessary (ideally under 48 hours) to prevent sunlight from drying out and cracking delicate plaster or shrinking vinyl liners.
Q5: Can you drain a vinyl liner pool?
Draining a vinyl liner pool completely is not recommended without specialized vacuum equipment, as the liner will shrink, wrinkle, and pull away from corners when dried out.
Q6: How long does it take to drain a 20,000-gallon pool?
Using a standard 2-inch commercial submersible pump flowing at 35 to 50 gallons per minute, draining takes between 10 and 14 hours.
Q7: How much does it cost to refill a pool with city water?
Refilling an average 20,000-gallon pool costs between $80 and $220 on your municipal water utility bill, based on average city rates of $4 to $10 per 1,000 gallons.
Q8: What is cyanuric acid and why does it force you to drain?
Cyanuric acid (CYA) is a chlorine stabilizer that does not evaporate. When CYA levels rise above 100 ppm from chlorine tablets, it locks up chlorine effectiveness, forcing a drain and refill.
Final Thoughts & Key Takeaways
In conclusion, understanding how much does it cost to drain a pool? provides essential clarity, practical strategies, and actionable advice. By incorporating these foundational insights, adhering to verified safety guidelines, and following structured best practices, you ensure reliable, long-term outcomes while preventing common mistakes. Stay informed, consult certified professionals when needed, and maintain consistent quality care.