Filling a swimming pool costs €40-2,000 depending on pool size, water source, and fill method. Municipal water via garden hose costs €4-10 per 1,000 gallons (€40-200 for typical 10,000-20,000 gallon pools). Water delivery trucks cost €200-600 per truckload (6,000 gallons typical capacity), totaling €400-2,000 for most residential pools. Well water is free but requires electricity to run a pump (€25-75) and potential chemical treatment for minerals.
Understanding fill costs helps budget for new pool installations, spring openings after winter drainage, or emergency refills after repairs. This comprehensive guide covers calculation methods for different pool shapes, comparison of fill options (municipal, well, delivery service), timing considerations, and cost-saving strategies including sewer charge waivers.
Key Takeaways
- Municipal water (garden hose): €4-10 per 1,000 gallons – cheapest option, takes 12-36 hours
- Water delivery service: €200-600 per truckload (6,000 gallons) – fastest option (1-3 hours), most expensive
- Well water: Free water, €25-75 electricity – no water cost, risks well pump damage from extended use
- Average 17,000-gallon pool: €70-170 municipal water, €500-1,700 delivery service
- Sewer charge waiver: Save €100-300 – most municipalities waive sewer fees for documented pool fills
- Fill time: 12-36 hours garden hose, 1-3 hours water truck delivery
- Portugal context: Municipal water rates vary by region; delivery services less common than US/northern Europe
How to Calculate Pool Volume
Before determining fill costs, calculate your pool’s water volume in gallons or liters.
Rectangular Pools
Formula: Length × Width × Average Depth × 7.5 = Gallons
Example: 40 ft × 20 ft × 5 ft average depth × 7.5 = 30,000 gallons
Metric conversion: Multiply cubic meters by 1,000 for liters (1 m³ = 1,000 liters = 264 gallons)
Oval/Circular Pools
Formula: Diameter A × Diameter B × Average Depth × 5.9 = Gallons
Example: 30 ft × 20 ft × 4 ft average depth × 5.9 = 14,160 gallons
Round pools: Use the same formula with identical diameter measurements for A and B.
Kidney-Shaped/Irregular Pools
Method 1: Divide pool into sections (rectangular, circular), calculate each section separately, sum totals.
Method 2: Use an online pool volume calculator (input shape, dimensions).
Method 3: Consult pool installation documentation as volume is typically specified by the builder.
Average Depth Calculation
Most pools have shallow and deep ends. Average depth = (Shallow depth + Deep depth) ÷ 2
Example: Shallow end 3 ft, deep end 7 ft → Average depth = (3 + 7) ÷ 2 = 5 ft
Common Pool Sizes and Volumes
Small pools: 10,000-15,000 gallons (38,000-57,000 liters)
Medium pools: 15,000-25,000 gallons (57,000-95,000 liters)
Large pools: 25,000-40,000+ gallons (95,000-150,000+ liters)
Olympic-size pool: 660,000 gallons (2.5 million liters) and residential pools rarely approach this size
Fill Option 1: Municipal Water (Garden Hose)
Cost Structure
Water rate: €4-10 per 1,000 gallons (varies by municipality)
Sewer charges: €5-15 per 1,000 gallons (often waivable for pool fills)
Combined cost without waiver: €9-25 per 1,000 gallons
Combined cost with sewer waiver: €4-10 per 1,000 gallons
Cost Examples by Pool Size
10,000-gallon pool: €40-100 (with sewer waiver)
15,000-gallon pool: €60-150
20,000-gallon pool: €80-200
30,000-gallon pool: €120-300
Fill Time
Standard garden hose (5/8 inch diameter, 60 PSI water pressure): 450-550 gallons per hour
10,000-gallon pool: 18-22 hours
15,000-gallon pool: 27-33 hours
20,000-gallon pool: 36-45 hours
Two hoses simultaneously: Cut time in half (15,000-gallon pool fills in 13-16 hours)
Procedure
- Place garden hose in deep end of pool (prevents damage to liner/finish from water pressure)
- Turn on water to full flow
- Monitor periodically and adjust hose position if needed to prevent displacement
- Check water level every 4-6 hours
- Stop when water reaches proper level (midpoint of skimmer opening)
Caution: Never let an unattended hose overflow pool as it can flood the surrounding area, damage landscaping, and waste water.
Advantages
Cheapest option: Significantly less expensive than water delivery service.
Convenient: Most homeowners have garden hose and water access.
No scheduling: Fill whenever desired, no appointment required.
No minimum order: Fill any amount needed (top-offs, partial fills).
Disadvantages
Slow: Requires 12-36+ hours for typical residential pools.
Monitoring required: Must check periodically to prevent overflow.
Delays pool use: Cannot swim until water fully fills and chemicals balanced (additional 24-48 hours).
Potential municipal restrictions: Some areas restrict water use during droughts or peak summer months.
Fill Option 2: Water Delivery Service
Cost Structure
Per-truckload pricing: €200-600 per truck (6,000-gallon capacity typical)
Per-gallon pricing: €0.03-0.10 per gallon
Rural delivery surcharge: €50-150 for locations beyond standard service area
Hose extension fee: €20 per 50 feet beyond included 200 feet (some companies)
Emergency/weekend delivery premium: €75-200 additional
Cost Examples by Pool Size
10,000-gallon pool: €400-1,000 (2 truckloads)
15,000-gallon pool: €600-1,500 (2-3 truckloads)
20,000-gallon pool: €800-2,000 (3-4 truckloads)
30,000-gallon pool: €1,200-3,000 (5 truckloads)
Fill Time
Single truck: 30-60 minutes to unload 6,000 gallons
Multiple trucks: Companies schedule trucks 1-2 hours apart (allows time for first truck to unload before second arrives)
Total fill time: 1-3 hours for most residential pools
Procedure
- Contact water delivery company, schedule date/time
- Provide pool location, estimated volume, property access details
- Company dispatches trucks on scheduled day
- Driver connects hose from truck to pool, pumps water
- Process repeats for multiple truckloads if needed
- Payment upon completion
Water Types Available
Municipal water: Standard option, pre-treated for potable use (safe for swimming), requires chemical balancing.
Pre-chlorinated water: Premium option, includes baseline chlorination (higher cost €50-100 per load), reduces chemical balancing time.
Well water: Some companies offer well-sourced water (cheaper), may require more chemical treatment due to minerals.
Advantages
Speed: Fills pool in 1-3 hours versus 12-36+ hours with hose.
Convenience: Hands-off process. The company handles the entire fill.
Immediate use: Water ready for chemical balancing and swimming sooner (pre-chlorinated option may be swim-ready immediately).
Well pump protection: Avoids stressing residential well pump with extended 24-48 hour runtime.
Leak detection: Rapid fill reveals leaks quickly (easier to spot issues before pool fully fills).
Disadvantages
Expensive: Costs 5-10 times more than municipal water via hose.
Scheduling required: Must coordinate delivery date/time, potential delays if trucks are unavailable.
Access requirements: Delivery trucks require adequate driveway/street access (narrow driveways, low-clearance obstacles may prevent access).
Rural surcharges: Remote locations pay a premium for extended travel distance.
Fill Option 3: Well Water
Cost Structure
Water: Free (no municipal water charges)
Electricity: €25-75 to run well pump 24-48 hours (varies by pump size, electricity rates, fill duration)
Chemical treatment: €50-150 for additional chemicals to balance mineral-heavy well water (iron, manganese, calcium, pH adjustment)
Total cost: €75-225
Fill Time
Typical residential well pump: 5-10 gallons per minute (GPM)
10,000-gallon pool: 16-33 hours (5 GPM), 8-16 hours (10 GPM)
15,000-gallon pool: 25-50 hours (5 GPM), 12-25 hours (10 GPM)
20,000-gallon pool: 33-67 hours (5 GPM), 16-33 hours (10 GPM)
Procedure
- Connect garden hose to outdoor spigot supplied by well
- Place hose in deep end of pool
- Turn on water to full flow
- Monitor well pump operation and make sure to take breaks every 4-6 hours to allow well to recharge
- Stop fill when water reaches proper level
Critical: Continuous well pump operation for 24-48 hours risks:
- Well depletion (pump draws water faster than aquifer recharges)
- Sediment stirring (cloudy water entering pool)
- Pump overheating/failure (€1,500-6,500 replacement cost)
Well Water Quality Issues
Iron and manganese: Causes rust-colored staining on pool surfaces, requires metal sequestrant chemicals.
High pH: Well water often alkaline (pH 7.8-8.5+), requires muriatic acid to lower.
Hard water: High calcium/magnesium causes scaling on tiles, equipment – requires calcium reducers or partial drain-refill cycles.
Sulfur (hydrogen sulfide): “Rotten egg” smell, requires shock treatment and filtration.
Sediment: Particulates from aquifer – requires extensive filtration, may clog filter rapidly.
Advantages
No water cost: Free water (only electricity expense).
Immediate availability: No scheduling, no waiting for delivery.
Unlimited supply: Can fill pool, top off periodically, no restrictions (subject to well capacity).
Disadvantages
Well pump stress: Risk damaging pump with extended continuous operation.
Slow fill: Similar to garden hose (12-48+ hours depending on well pump capacity).
Water quality issues: Requires additional chemical treatment for minerals, potential staining/scaling.
Well depletion risk: May leave the household without water for days if well depleted during fill.
Not suitable for all wells: Low-yield wells (< 5 GPM) may require days to fill the pool, impractical.
Sewer Charge Waivers
Why Sewer Charges Apply
Municipal water bills typically include two components:
Water supply charge: Cost of providing clean water to home.
Sewer/wastewater charge: Cost of treating wastewater returning to the municipal system via drains.
Problem: Pool water doesn’t return to the sewer system. It evaporates, splashes out, drains to the yard during backwashing. Paying sewer charges for pool fill is paying for service not received.
How to Obtain Waiver
Before filling pool:
- Contact local water utility billing department
- Request “pool fill credit” or “sewer charge adjustment”
- Provide pool volume estimate or measurement
- Some municipalities require proof (pool installation permit, builder documentation)
- Utility issues temporary meter read or account note
After filling pool:
- Contact utility after fill complete
- Request retroactive adjustment showing before/after meter readings
- Provide documentation (pool installation date, volume)
- Utility calculates excess water usage, credits sewer charges
Savings
10,000-gallon pool: €50-150 sewer charge waiver
15,000-gallon pool: €75-225 waiver
20,000-gallon pool: €100-300 waiver
Not all municipalities offer waivers so check local policy. Most cities/towns in the US, Canada, Europe offer some form of pool fill adjustment.
Municipal Water Restrictions
Drought Restrictions
Many regions impose water restrictions during drought conditions:
Odd/even watering days: Restricts outdoor water use to alternating days based on address.
Time restrictions: Prohibits outdoor water use during peak hours (e.g., 10 AM-6 PM).
Total outdoor bans: Severe drought may prohibit all non-essential outdoor water use including pool filling.
Fines: Violating restrictions can result in fines €50-500+ depending on severity and municipality.
Pool Filling Exemptions
New pool installations: Some municipalities exempt new pool fills from restrictions (one-time fill necessary for pool completion).
Emergency refills: Pool structural repairs requiring drainage may receive exemption.
Permit requirements: May require a permit or approval from the water utility before filling during restrictions.
Check Before Filling
Contact local water utility to confirm:
- Current water restrictions in effect
- Whether pool filling permitted
- Required permits or approvals
- Recommended fill timing (overnight, off-peak hours)
Cost Comparison Summary
10,000-Gallon Pool:
- Municipal water (hose): €40-100
- Well water: €25-75
- Water delivery: €400-1,000
15,000-Gallon Pool:
- Municipal water (hose): €60-150
- Well water: €40-110
- Water delivery: €600-1,500
20,000-Gallon Pool:
- Municipal water (hose): €80-200
- Well water: €55-145
- Water delivery: €800-2,000
30,000-Gallon Pool:
- Municipal water (hose): €120-300
- Well water: €80-220
- Water delivery: €1,200-3,000
6 Cost-Saving Strategies
1. Request Sewer Charge Waiver
Potential savings: €50-300 depending on pool size.
Required action: Contact water utility before or immediately after filling.
2. Fill During Off-Peak Hours
Some municipalities offer reduced rates for water use during off-peak hours (typically overnight 10 PM-6 AM).
Savings: 10-20% reduction in water rates (varies by municipality).
3. Use Two Hoses Simultaneously
Cuts fill time in half: 15,000-gallon pool fills in 13-16 hours instead of 27-33 hours.
Reduces monitoring burden: Less total time monitoring hose.
Caution: Ensure adequate water pressure (may reduce if both hoses are on the same supply line).
4. Partial Fill with Municipal + Top Off After Initial Chemistry
Strategy: Fill pool to 80-90% with municipal water, balance chemistry, then top off final 10-20% over following days/weeks as needed.
Benefit: Spreads water usage across multiple billing cycles (may avoid highest tier pricing if municipality uses tiered water rates).
5. Capture Rainwater (Limited Application)
Realistic impact: Minimal. Rooftop rainwater collection systems capture 100-500 gallons per significant rainfall event. It would require months of heavy rainfall to fill the pool.
Better use: Capture rainwater for pool top-offs during season (offsets evaporation, reduces annual water costs).
6. Negotiate Delivery Service Quotes
Shop multiple companies: Get quotes from 3-5 water delivery services, negotiate based on competitors’ pricing.
Off-peak scheduling: Request weekday morning delivery (avoid premium weekend/evening fees).
Bulk discount: If neighbors also need fills, coordinate simultaneous deliveries as some companies offer multi-home discounts.
When to Fill or Refill Pool
New Pool Installation
Timing: Immediately after pool construction is complete, before landscaping is installed.
Reason: Prevents structural stress on new pool shell, allows leak testing, starts water chemistry balancing process.
Spring Opening
Timing: Most pools maintain water through winter (lowered below skimmer but not drained). Refill to normal level in spring before opening.
Typical addition needed: 500-2,000 gallons to restore normal level.
After Repairs
Major repairs (liner replacement, structural crack repair, replastering) require draining the pool. Refill immediately after repair is completed.
Critical for fiberglass pools: Fiberglass pools must remain filled. Empty shells can pop out of the ground from groundwater pressure.
After Severe Leak
Emergency refill needed if leak drained significant water volume before detection/repair.
Portugal Context
Municipal Water Rates
Portugal water rates vary significantly by region and municipality:
Lisbon area: €1.50-3.00 per cubic meter (1,000 liters)
Porto area: €1.20-2.50 per cubic meter
Algarve region: €1.80-3.50 per cubic meter (higher due to tourism demand, water scarcity)
Rural areas: €0.80-2.00 per cubic meter
Conversion: 1,000 liters = 264 gallons → Portugal rates approximately €5.70-13.20 per 1,000 gallons
Water Delivery Services
Less common in Portugal than US/northern Europe. Most pool owners use municipal water via hose due to:
- Relatively affordable municipal water rates
- Smaller average pool sizes (8-15 cubic meters / 2,000-4,000 gallons typical)
- Mild climate (pools refilled infrequently, annual spring top-off sufficient)
When available: Water delivery trucks in Portugal typically serve commercial operations, construction sites, rural properties without municipal water. Residential pool fills via delivery less established as service.
Well Water (Poços)
Rural Portugal: Many properties have wells (poços or furos). Well water is common for irrigation, pool filling in non-urban areas.
Considerations: Portuguese well water often high in calcium (limestone aquifers common), requires calcium sequestrant chemicals, may cause scaling.
Drought Restrictions
Summer drought restrictions increasingly common in southern Portugal (Algarve, Alentejo) due to climate change:
- Outdoor water use restrictions June-September during severe drought years
- Pool filling restrictions or bans during peak drought
- Fines for violations
Check with the local Câmara Municipal (municipal government) for current water restrictions before filling.
Conclusion
Filling a swimming pool costs €40-200 using municipal water via garden hose (12-36 hours fill time), €400-2,000 using water delivery service (1-3 hours), or €25-75 electricity using well water (12-48 hours, free water but risks well pump damage). For a typical 15,000-gallon residential pool, municipal water via hose costs €60-150, making it the most economical choice for most pool owners.
Calculate pool volume before obtaining quotes: rectangular pools (Length × Width × Average Depth × 7.5), oval pools (Diameter A × Diameter B × Average Depth × 5.9). Request sewer charge waiver from water utility to save €50-300 on pool fills as most municipalities waive sewer fees for documented pool fills since water doesn’t return to the wastewater system.
Water delivery services offer speed and convenience (1-3 hours fill time, hands-off process, optional pre-chlorinated water) but cost 5-10 times more than municipal water. Best suited for well water users (protects well pumps from extended runtime stress), new pool installations requiring immediate use, or properties in areas with high municipal water restrictions. Garden hose remains the most practical option for the majority of residential pool fills, offering significant cost savings with reasonable fill time requiring only periodic monitoring.
FAQ
How much does it cost to fill a 10,000 gallon swimming pool?
Filling a 10,000-gallon pool typically costs $40–$120 (€35–€110) using municipal water, depending on local water rates. In some areas, it can be higher if water is expensive or if tanker delivery is required instead of a standard hose fill.
How much to fill a 20,000 litre pool?
A 20,000-litre pool usually costs around €20–€60 to fill with tap water in most European regions. The exact price depends on your local cost per cubic meter (1,000 litres) and any additional service fees.
What is the cheapest way to fill a pool with water?
The cheapest method is usually using your home tap water with a hose. It’s slower but far cheaper than water delivery trucks. If allowed locally, collecting rainwater or using a well can reduce costs even further.
How big is a 10,000 litre pool?
A 10,000-litre pool is relatively small – about 2.5 m × 2 m × 2 m (roughly) or a compact above-ground pool. It’s suitable for cooling off rather than full swimming, holding about 2,600 gallons of water.
