Pool Fill Cost Calculator
Estimate the cost to fill or top off a swimming pool. Compare city/tap water vs. bulk water delivery, account for sewer charges and the common pool-fill exemption, and see the fill time.
Estimate what it costs to fill or top off your pool. Enter the volume and your water and sewer rates — the tool shows your tap-water cost, what bulk delivery would run, and whether a sewer exemption is worth chasing.
Pool volume
Enter your pool's volume in gallons if you know it, or switch to dimensions to estimate it.
Volume in gallons
Total gallons to add. For a full fill, use your pool's capacity; for a top-off, estimate the gallons needed.
Water rate
What your utility charges per 1,000 gallons of water. Find it on your water bill; the U.S. average is roughly $4–$6.
Sewer rate
What your utility charges per 1,000 gallons for sewer, often billed on water use. Frequently higher than the water rate. Set to 0 if you're on a septic system.
Pool-fill sewer exemption
Turn on if your utility waives sewer charges on a pool fill (many do, on request). Removes the sewer charge from the estimate.
Cost to Fill (City Water)
$240
for 20,000 gallons of tap water
Ask your utility to waive the sewer charge
Your sewer charge is as large as the water itself — because many utilities bill sewer on metered water use, even though pool-fill water never enters the sewer. Most will waive it for a pool fill if you ask: call before you fill and request a pool-fill credit or a temporary deduct-meter reading. Toggle the exemption above to see what you'd save.
Estimates use your entered rates plus 2026 national averages for bulk water delivery (about $0.05–$0.12 per gallon) and a typical garden-hose flow (~9 gallons per minute). Water delivery is usually far pricier than tap water and mainly makes sense for homes on a private well that can't supply the volume, or with no municipal service. Your actual bill varies with local rates, tiered pricing, and seasonal surcharges — check your utility's pool-fill policy before a large fill.
💡About this calculator▼
Filling a pool is one of those costs that's easy to underestimate — the water itself is cheap per gallon, but a pool holds tens of thousands of gallons, and a hidden sewer charge can quietly double the bill. This calculator gives you a realistic number before you turn on the hose or call a water-delivery company.
Enter your pool's volume (in gallons, or estimated from its dimensions) and your local water and sewer rates, which are on your utility bill. The tool shows what a tap-water fill costs, what bulk water delivery would run as an alternative, and roughly how long a garden hose would take to fill it.
The two things that actually move the number are the sewer charge and your fill method. Many utilities bill sewer based on the water you use — but pool-fill water never enters the sewer, so most offer a "pool fill" exemption or credit if you ask. And while tap water is almost always cheaper than hiring a delivery truck, delivery is the practical option for homes on a private well or with no municipal service. This tool helps you see all of it at a glance.
The calculator starts from your pool's volume in gallons. If you don't know it, switch to dimensions and it estimates the volume from length × width × average depth (one cubic foot of water is about 7.48 gallons).
For the city/tap water cost, it applies your two utility rates — both billed per 1,000 gallons. The water charge is your volume times the water rate. The sewer charge is your volume times the sewer rate, unless you flag the pool-fill exemption, in which case it's removed. Added together, those are your tap-water total. Sewer rates are often higher than water rates, which is why the sewer line can be the biggest single piece of the bill.
For the water delivery alternative, it applies a typical bulk pool-fill price range — roughly $0.05 to $0.12 per gallon delivered — to your volume. That's far more per gallon than tap water, because you're paying for trucking, not just the water. Delivery mainly makes sense when a private well can't supply the volume fast enough, or when there's no municipal water at all.
Finally, it estimates the fill time for a standard garden hose at about 9 gallons per minute, so you can see whether a tap fill is an afternoon or a multi-day project. The exact formula and a worked example are below.
📐How it's calculated▼
The estimate is built from your volume and your local rates, with a separate delivery comparison.
Step 1 — Volume: If entered directly, gallons = your input. From dimensions: gallons = Length × Width × Average depth × 7.48
Step 2 — City/tap water: Water charge = (Gallons ÷ 1,000) × Water rate Sewer charge = (Gallons ÷ 1,000) × Sewer rate — or $0 if the pool-fill exemption applies City total = Water charge + Sewer charge
Step 3 — Water delivery (alternative): Delivery = Gallons × $0.05 to $0.12 per gallon
Step 4 — Fill time (garden hose): Hours ≈ Gallons ÷ (9 gallons per minute × 60)
Example: A 20,000-gallon pool, $5/1,000 gal water, $7/1,000 gal sewer, no exemption
→ Water charge: (20,000 ÷ 1,000) × $5 = $100
→ Sewer charge: (20,000 ÷ 1,000) × $7 = $140
→ City total: $100 + $140 = $240
→ Water delivery: 20,000 × $0.05–$0.12 = $1,000–$2,400
→ Fill time: 20,000 ÷ 540 ≈ 37 hours (about 1.5 days)
Notice the sewer charge ($140) is larger than the water itself ($100) — and waiving it with a pool-fill exemption would cut the bill from $240 to $100.
📎Source: U.S. Environmental Protection Agency — WaterSense
🔍Finding your inputs▼
Pool volume: Enter gallons directly if you know your pool's capacity (it's often on the original paperwork or the builder's spec). If not, switch to dimensions and enter the length, width, and average depth in feet, and the tool estimates the gallons for you. For a top-off rather than a full fill, enter just the gallons you need to add.
Average depth: Only needed in dimensions mode. Add your shallow-end depth and deep-end depth and divide by two. For a pool that's 3 feet at the shallow end and 8 at the deep end, the average is 5.5 feet. A constant-depth pool just uses that depth.
Water rate: What your utility charges per 1,000 gallons of water. It's printed on your water bill, sometimes shown per CCF (one CCF = 748 gallons) — if so, divide the CCF rate by 0.748 to get the per-1,000-gallon figure. The U.S. average is roughly $4 to $6 per 1,000 gallons, but it varies widely by city.
Sewer rate: What your utility charges per 1,000 gallons for sewer service, which is very often billed based on the water that runs through your meter. It's frequently higher than the water rate itself. Find it on the same bill. If you're on a septic system rather than municipal sewer, set this to 0 — there's no sewer charge to worry about.
Pool-fill sewer exemption: Leave this off to see your full bill including sewer. Turn it on if your utility waives sewer charges on a pool fill — many do, but usually only if you request it in advance. It removes the sewer charge from the estimate so you can see exactly what the exemption is worth.
⚠️Special situations▼
My sewer charge is bigger than the water cost
That's common and it's exactly what the pool-fill exemption is for. Because many utilities calculate sewer charges from your metered water use, a big pool fill generates a large sewer bill for water that never enters the sewer. Call your water provider before you fill and ask about a pool-fill credit, a sewer exemption, or a deduct/secondary meter — most offer one of these. Some want a meter reading immediately before and after the fill, so ask how they handle it. Toggling the exemption on here shows you exactly what's at stake.
I'm on a private well, not city water
Your tap water is effectively free, but the constraint is your well's recovery rate and pump. Filling a pool can draw the well down faster than it refills, leaving you without water and potentially running the pump dry, which can damage it. Many well owners fill in stages over several days, or hire bulk water delivery to fill quickly without stressing the well — switch the comparison to the delivery figure to budget for that. If you do fill from the well, watch your pressure and give the well time to recover.
I just need to top off after evaporation or a drain-down
Enter only the gallons you need to add, not the pool's full capacity. A typical pool loses a quarter to a half inch a day to evaporation in summer — over a large surface that adds up, but a top-off is a small fraction of a full fill. If you're refilling after partially draining for maintenance, estimate the inches you dropped and multiply by your pool's gallons-per-inch, or just use the dimensions mode with the depth you're replacing.
There are water restrictions or a drought where I live
Filling a pool uses a lot of water at once, and many areas restrict or surcharge large fills during droughts — some require a permit, limit fills to certain times, or charge a premium tier. Check with your municipality before filling, especially for a brand-new pool. Where restrictions are tight, scheduled water delivery is sometimes the only allowed option, and a pool cover afterward dramatically cuts evaporation so you refill far less often.
Should I fill it myself or hire delivery?
For homes on municipal water, filling from the tap is almost always far cheaper — often by 5 to 10 times — even after sewer charges. Delivery wins on convenience and speed (a few trucks versus a day or two of hose time) and is the practical choice when a well can't keep up or there's no city water. Compare the two figures here: if the tap-water total is a fraction of the delivery range and your supply can handle it, the hose is the economical call.
❓Common questions▼
How much does it cost to fill a swimming pool with water?
For an average 15,000–25,000 gallon pool on city water, the water itself usually runs roughly $80–$200 at typical rates — but sewer charges can add as much again if they're not waived, pushing the total toward $150–$500. Bulk water delivery costs far more, commonly $1,000–$3,000 for the same pool. Enter your volume and local rates above for a number tailored to you.
Why does filling a pool add a big sewer charge?
Most utilities can't separately meter what goes down your drains, so they bill sewer based on the water that runs through your water meter — on the assumption it eventually enters the sewer. A pool fill breaks that assumption: the water stays in the pool, but it still registers on the meter and triggers a sewer charge. That's why the sewer line can be the biggest part of a fill bill, and why pool-fill exemptions exist.
Can I avoid the sewer charge when filling my pool?
Often, yes — but you usually have to ask in advance. Many water utilities offer a pool-fill exemption, a one-time sewer credit, or let you use a deduct (secondary) meter so the fill water isn't billed as sewer. Call your provider before filling and ask how they handle pool fills; some need a meter reading right before and after. Don't assume it's automatic — the charge typically stands unless you request the adjustment.
Is it cheaper to fill a pool with a hose or pay for water delivery?
On municipal water, a garden hose is almost always cheaper — frequently 5 to 10 times less than delivery, even counting sewer charges. Water delivery costs more because you're paying to truck the water in, but it's faster (hours of unloading versus a day or more of hose time) and is the realistic option for homes on a private well that can't supply the volume or with no city water. The comparison above shows both for your pool.
How long does it take to fill a pool with a garden hose?
A standard garden hose delivers roughly 9 gallons per minute, so a 20,000-gallon pool takes around 37 hours — well over a day of continuous running. Larger pools or lower water pressure take longer; using two hoses roughly halves the time. Never leave a filling pool unattended for long stretches, both to avoid overflowing (which wastes water you're paying for) and because water levels are easy to lose track of overnight.