Filling a Pool in Orlando: Your Tap Water’s Starting Numbers
Filling a pool in Orlando means starting from Orlando Utilities Commission (OUC)’s water — which is hard at roughly 129 mg/L total hardness (about 7.5 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
Reading scale-versus-etch direction needs hardness, alkalinity and pH together, and Orlando Utilities Commission (OUC) does not publish alkalinity or pH. That direction cannot be computed from public data for this city and we are not going to guess it — a drop-count test kit reads all of it in about five minutes once the pool is full.
The top-off arithmetic
Evaporation removes pure water and leaves the minerals behind, so make-up water re-adds Orlando hardness every time. Replacing one full pool volume through top-off adds roughly another 129 ppm; starting from a fresh fill at about 129 mg/L, that reaches the 400 ppm ceiling after about 2.1 pool volumes of make-up water — a couple of pool volumes, which a high-evaporation summer gets through faster than most owners expect. That is the 20th 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).
Why Orlando water is like this
Same limestone-carbonate origin as Jacksonville, but Orlando draws from the deeper LOWER Floridan beneath a confining clay layer, and the resulting water is noticeably softer – OUC publishes an average hardness of 129 ppm (7 grains per gallon), well below Jacksonville’s or Tampa’s. The single most useful thing for a pool owner to understand is what OUC adds and does not add. OUC does NOT soften and does NOT blend in surface water.
Its train is: well pumps -> ozone contact basins (ozone oxidizes hydrogen sulfide to kill the sulfur taste/odor and to cut the amount of chlorine needed) -> chlorine -> sodium hydroxide (caustic soda) to raise pH for corrosion control -> finished water storage. Sodium hydroxide raises pH and alkalinity but contributes ZERO calcium.
So Orlando fill water is a moderately soft water carrying a deliberately elevated pH – the utility says outright it adds sodium hydroxide ‘to increase the water’s pH and thus prevent corrosion.’ That combination is why Orlando pool owners typically fight rising pH and have to build calcium hardness UP toward target, rather than diluting hardness down the way a Jacksonville or Tampa owner does.
OUC also states its chlorine averages 1.0 ppm and that it does NOT use chloramines – so fill water reads honestly on a free-chlorine test.
Ozone as the advanced/primary treatment in ozone contact basins (hydrogen sulfide oxidation, taste and odor), then chlorine (average 1.0 ppm; OUC states it does not use chloramines), then sodium hydroxide for pH adjustment and corrosion control, with fluoride historically added. No lime softening, no surface-water blending, no desalination. Sodium hydroxide is the key pool-relevant choice: it lifts pH and alkalinity without adding hardness.
Background sources: ouc.com, orlando.gov, orangecountyfl.net, aws.sjrwmd.com.
Before you drain or refill in Orlando
TWO different pool-fill credit programs depending on WHICH utility serves the address – this trips people up.
- CITY OF ORLANDO (for OUC water customers inside the city): the City, not OUC, grants the sewer credit. Its own page says ‘Did you fill your swimming pool or have a water leak and need your sewer charges credited? You can request a credit from the city for the sewer portion of your OUC water charges.’ The pool-specific term is narrow: ‘When you renovate or resurface your pool, you can be eligible for a credit adjustment once per calendar year. We’ll determine the average water consumption during normal usage and adjust your sewer charges back to the standard cost.’ Requested by submitting an online request; if it qualifies the City adjusts the OUC bill within 1-2 billing cycles. Note the trigger is renovation/resurfacing – not a routine refill.
- ORANGE COUNTY UTILITIES (serves parts of unincorporated Orange County, NOT the City of Orlando): separate ‘Pool Fill Adjustment Request Form’ under Board of County Commissioners Resolution No. 2012-M-11, ‘Billing Adjustments For Excessive Water Consumption,’ effective May 8, 2012. Terms: adjustment available no more than once annually; wastewater portion of the bill ONLY; the customer’s prior 12-month average usage is used to recompute the wastewater charge for the spike month; NO adjustment on water charges and the tiered rate structure still applies; the customer must submit the pool contractor’s repair invoice/payment receipt showing the pool address, repair date, pool dimensions, and the date and amount of water used; must be filed within 60 days of the high consumption; the customer must pay the bill in full or make payment arrangements while it is processed. Form marks ‘New Pool’ or ‘Pool Repair.’ Submit to Orange County Utilities, 9150 Curry Ford Rd., or Adjustment.Request@ocfl.net, 407-836-5515.
- DROUGHT – IMPORTANT NEGATIVE FINDING: Orange County is NOT among the counties in the SJRWMD Phase III Extreme Water Shortage Order, whose scope I verified directly as Alachua, Baker, Bradford, Clay, Duval, Flagler, Lake, Marion, Nassau, Putnam and St. Johns. So unlike Jacksonville, Orlando is NOT under the Phase III pool make-up-water duty or the aesthetic-use ban. Orlando instead follows SJRWMD’s standard year-round landscape irrigation rule; search results describe that as two days per week during daylight saving time (odd Wed/Sat, even Thu/Sun) and never 10 a.m.-4 p.m., but I did not open Orange County’s or OUC’s own restrictions page, so treat the specific schedule as REPORTED, not verified. Landscape irrigation rules do not regulate pool filling.
- DRAINING – statewide Florida rules apply: F.A.C. 62-302.530
- caps chlorine to surface waters at <=0.01 mg/L, and F.A.C. 64E-9.007
- requires pool waste water be discharged through an air gap to sanitary sewers, storm sewers, drainfields or other means in accordance with local requirements and permits.
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 Jacksonville — Same state, different water: Jacksonville fills at about 246 mg/L against 129 here.
Source: OUC Water Services / 2025 Water Quality Report (2025 report data), accessed 2026-08-10. 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.