The pool is empty. The plaster is fresh off an acid wash, the deep end has a puddle in it, and someone in the house has already asked how long until they can swim. Two options come up: run the garden hose for a day or two, or pay for pool water delivery and have a truck fill it in an afternoon.

Drains and acid washes are part of pool service in Newbury Park and around the Conejo Valley, and the refill question comes up every time. So here’s the honest version, with real local water rates.

How many gallons are you actually refilling?

Start here, because every other number depends on it. For a rectangular pool, multiply length by width by average depth in feet, then multiply by 7.48. That’s the number of gallons in a cubic foot, and it’s the same conversion water utilities use when they bill you.

A 15 by 30 foot pool with an average depth of 5.5 feet holds about 18,500 gallons. Angi’s 2026 cost guide uses 17,000 gallons as the average pool, so that example is in the normal range. Freeform pools are harder to measure, and your original plans or the builder’s paperwork may list the volume.

What a garden hose fill costs on local water rates

Local water bills count water in hundred cubic feet, shown as CCF or HCF. The Cal Water residential rate schedule for its Westlake district, effective July 1, 2026, defines one CCF as about 748 gallons and prices it in four tiers:

The first 6 CCF cost $1.78 each. From 7 to 25 CCF, it’s $7.11. From 26 to 44 CCF, $8.90. Over 44 CCF, $10.67.

An 18,500-gallon refill is about 24.7 CCF on top of whatever the house normally uses, so most of it lands in the upper tiers. At $7.11 per CCF, the pool’s water costs about $175. At $8.90, about $220. If the refill pushes the bill past 44 CCF, the top tier puts it near $265. That’s roughly $9.50 to $14.26 per 1,000 gallons.

Your numbers will differ if you’re on the City of Thousand Oaks, California American Water or another provider, so pull up your own rate sheet. The method is the same: gallons divided by 748, times your tier price.

How long the hose takes

This is where the hose loses points. Flow depends on water pressure, hose diameter and hose length. An Oregon City water guide puts a 25-foot, half-inch hose at 24 gallons per minute at 40 psi, but says a 100-foot hose drops to just 6 gallons per minute.

At 6 gallons per minute, 18,500 gallons takes about 51 hours. Two hoses on separate spigots roughly halve that. Angi’s guide says a couple of garden hoses usually fill an average pool in 12 to 24 hours, which fits shorter hoses and decent pressure.

The quickest way to know your own number: time how long it takes to fill a 5-gallon bucket. If it fills in 30 seconds, you’re getting 10 gallons per minute. Divide your pool’s gallons by that, and you have your answer in minutes.

Hose vs truck, side by side

When pool water delivery makes sense

Angi’s 2026 guide puts truck delivery at $30 to $100 per 1,000 gallons, which works out to about $555 to $1,850 for an 18,500-gallon pool. Some companies only sell by the full truckload, so you may pay for more than you need.

That premium buys speed. It’s worth it if the pool is part of a house sale closing this week, a commercial pool that needs to reopen, or a property where the water pressure is so low the hose would run for days. Ask the hauler where the water is sourced, and whether the truck can actually reach your yard. A long hose run over landscaping is part of the job.

Check the local water rules before you drain

Ventura County has restricted pool refills before. During the 2022 drought emergency, the City of Thousand Oaks prohibited draining and refilling pools by more than one foot with potable water, and the Ventura County Waterworks Districts serving Moorpark, Bell Canyon, Somis and Lake Sherwood banned refills over one foot and initial fills of residential pools.

The Conejo Valley’s emergency restrictions were lifted in March 2023, with outdoor watering back to two days a week. When we checked Cal Water’s alert center in October 2026, it showed no water shortage stage for the Westlake district. Under Cal Water’s staged plan, though, filling swimming pools is prohibited at Stage 4. A dry winter can change the rules, so check with your provider before you drain, not after. Our post on how often a pool should actually be drained covers if you need to drain at all.

The startup chemistry after a refill

Fresh water is not finished water. Calleguas, which supplies imported water to the Conejo Valley’s providers, lists its main supply at a pH of 8.3, alkalinity around 98 ppm and total hardness around 140 ppm in its 2025 water quality report.

Compare that to Raypak’s heater water chemistry targets for non-fiberglass pools: pH 7.6 to 7.8, alkalinity 80 to 120 ppm, and calcium hardness 200 to 400 ppm. So a fresh fill usually needs acid to bring pH down, and may need calcium added. It also has zero stabilizer, so cyanuric acid has to go in to reach the 30 to 50 ppm range the Oregon Health Authority recommends, and chlorine has to be built up right away.

New plaster has its own startup routine, covered in our post on what a full pool replaster costs. If the drain is for an acid wash, our draining and acid washing service page explains how that job runs.

Don’t run the pump until the water is there

Leave the equipment off until the water is well up into the skimmer opening and covering the returns. A pump that runs dry or sucks air cooks its shaft seal, and that’s how a refill turns into a pool pump repair.

Keep the hose end in the deep end so it isn’t scouring one spot of fresh plaster, and check on it. Nobody wants to discover the pool overflowed into the side yard at 2 a.m.

Asked at the pad, every week

Can I swim while it’s filling? Wait until it’s full and the chemistry is balanced and chlorinated.

Is truck water better than tap water? Not necessarily. Your tap water has a published quality report. Truck water depends on where the hauler fills up, so ask.

Will a refill spike my bill? Yes, for one cycle. On tiered rates, most of the pool’s water gets billed at your higher tiers.

Planning a drain and refill?

Tell us about the pool, why it’s being drained, and whether the plaster needs work. We’ll walk you through timing, the refill and the startup chemistry. Reach us through our contact page.

We service Pentair, Jandy, Zodiac, Hayward and Sta-Rite equipment, or call (805) 586-2055.