Filling a Pool in Chandler: Your Tap Water’s Starting Numbers
Filling a pool in Chandler means starting from City of Chandler Public Works & Utilities Department’s water — which is very hard at roughly 230 mg/L total hardness (about 13.5 grains per gallon). Here is what those published numbers actually do to a pool — and what they do not.
Which way this water pushes a pool
At a typical 84 F pool temperature the published City of Chandler Public Works & Utilities Department numbers index at +0.36 — inside the balanced band (how this is calculated). That puts Chandler 10th of the 15 cities here that publish enough to compute an index, counting from the most scale-forming down.
Since utilities publish TOTAL hardness and the index wants the CALCIUM fraction, +0.36 is a ceiling and the true figure sits at or below it — which for a near-balanced reading means Chandler water can test slightly aggressive once it is in the pool. Worth knowing before you assume balanced water needs nothing.
The top-off arithmetic
Evaporation removes pure water and leaves the minerals behind, so make-up water re-adds Chandler hardness every time. Replacing one full pool volume through top-off adds roughly another 230 ppm; starting from a fresh fill at about 230 mg/L, that reaches the 400 ppm ceiling after about 0.7 pool volumes of make-up water — less than one full pool volume — a hot-summer pool can work through that in a season or two, not decades. That is the 9th shortest budget of the 27 cities in this lookup.
Evaporation-only and deliberately the fastest case: splash-out, backwash and rain all dilute, and this uses published total hardness rather than the calcium fraction a kit reads (how this is calculated).
How much your own tap may differ
City of Chandler Public Works & Utilities Department reports hardness spanning 173 to 288 mg/L — a 1.7x range end to end. That is not measurement noise. It is what blending different sources into different service zones does over a year, and it means the single number at the top of this page is an average your own tap may not match. A pool a few neighbourhoods away can legitimately fill at a different hardness than yours. Test what comes out of your hose; do not plan off the midpoint.
Why Chandler water is like this
That 4x spread is not measurement noise – it is the groundwater blend. Chandler’s fossil groundwater and its treated surface water are chemically different, and the city states that areas WEST OF PRICE ROAD receive a blend of surface water and ground water. So a Chandler pool owner west of Price Road is filling from a different mix than one to the east, and a citywide average of 16.5 gpg would badly mislead either of them.
Chandler is candid that it does not treat for hardness on cost grounds: it notes 91 percent of its water is not used for household purposes and less than 1 percent is consumed, so additional treatment would not be economically practical.
Chandler also runs FREE CHLORINE rather than chloramine, targeting a residual of 1.0 to 2.0 mg/L and typically running about 1.6 mg/L in the distribution system – meaningfully higher than a trivial trace, which matters when calculating starting sanitizer and chlorine demand on a fresh fill. Fluoride is added at the Surface Water Treatment Plant to 0.7-1.0 ppm; groundwater gets no added fluoride but averages 0.9 ppm naturally.
All ground and surface water is disinfected with FREE CHLORINE (not chloramine) prior to entering the distribution system, targeted at 1.0-2.0 mg/L residual, typically 1.6 mg/L. No softening. Fluoride added at the Surface Water Treatment Plant (0.7-1.0 ppm). In 2024 Chandler built the Reclaimed Water Interconnect Facility, a membrane treatment facility that treats SRP and CAP water and conveys it to one of Chandler’s three aquifer recharge facilities.
Background sources: chandleraz.gov, azmet.arizona.edu, amwua.org.
Before you drain or refill in Chandler
DRAINING: the city prefers all pool and spa water discharges be kept on private property or put into the sanitary sewer clean-out; the best place to drain is your landscape. NO PERMIT is needed to drain your pool if it goes into the sanitary sewer clean-out or is maintained on your property. Pipes ‘hard plumbed’ to discharge off property (i.e. to the street) are PROHIBITED and are considered a direct connection to the storm drain.
Do not install the pool drain line as a permanent fixture – it may violate the city plumbing code or county health regulations and could contaminate the water when you refill. Recommended flow rate no greater than 12 gallons per minute, less depending on drain line size, distance to the sewer main and pipe condition. If you cannot locate the sanitary sewer clean-out, an EXCEPTION to drain into the street can be requested. Chandler does not keep records of clean-out locations on private property.
Environmental Management contact for exceptions: 480-782-3503. REFILLING: you are NOT required to contact the city when refilling your pool, but the city warns of the rise in your utility bill from the large consumption, and states flatly that THE CITY DOES NOT GIVE DISCOUNTS WHEN REFILLING YOUR POOL.
Critically, Chandler residential sewer customers pay a monthly base charge for sewer REGARDLESS of the amount of metered water use on the account – so unlike Phoenix, Mesa, Glendale and Scottsdale, a Chandler pool fill cannot inflate the sewer portion of the bill, and there is correspondingly no winter-averaging appeal to file. Only the metered water volume charge applies. DROUGHT: Chandler activated Stage One of its Drought Preparedness Plan in June 2022 and Stage One REMAINS ACTIVE.
Stage One is monitoring, public awareness campaigning, expanded conservation messaging and municipal water loss audits – it imposes NO restriction on residential pool filling.
Escalation path: Stage Two (surface supplies down more than 20 percent) brings mandatory reductions to municipal water use within CITY FACILITIES only; Stage Three (down more than 50 percent) shifts to groundwater reserves plus voluntary reduction campaigns; Stage Four (down more than 70 percent, declared by City Council) brings mandatory restrictions designed to reduce peak summer demand.
Rules change and enforcement varies — confirm with your water provider before draining or refilling. Nothing here is legal advice.
Worth a look next door
- Filling a pool in Mesa — Same state, different water: Mesa fills at about 290 mg/L against 230 here.
- Filling a pool in Houston — The other end of the scale: Houston gets about 2.6 pool volumes of top-off against 0.7 pool volumes here.
Source: City of Chandler 2025 Drinking Water Quality Consumer Confidence Report (PWS AZ04-07-090) (2025 report data), accessed 2026-08-11. Values are the utility’s published system-wide figures; your tap can vary by service zone and season.
Data page generated 2026-08-15. Part of the pool fill-water lookup.