Find your town: who supplies your water, and what changes

Almost everyone in this corner of Florida drinks water pumped from the Floridan aquifer, but a dozen different utilities pump and treat it. Groundwater supplies over nine in ten residents of this part of the state, by the water district's count. What differs from town to town is the treatment plant, the disinfectant and how the rotten-egg sulfide gets taken out.

A mailing address is not always a good clue. City limits, county service areas and old private systems overlap, so the surest check is the name printed on your water bill. Once you know it, find that utility below and open its own report.

Longwood

The City of Longwood pumps from five Floridan wells, 300 to 500 feet deep, and aerates the water to strip out hydrogen sulfide before it is chlorinated. Its 2025 Consumer Confidence Report lists chlorine at 1.68 ppm on average. Hardness is not in the report, so ask the city or test at home.

Not every Longwood-area address is on city water. Some homes nearby are served by Seminole County Utilities, which buys water for those areas from a private utility, so check the bill before you read a report. Watering days follow the county and district schedule described in the next sections.

Lake Mary

Lake Mary runs a single treatment plant fed by six upper Floridan wells. Instead of plain aeration, the city's 2025 report describes ultraviolet light advanced oxidation with hydrogen peroxide, then granular activated carbon and chlorination. Chlorine averaged 0.58 ppm in 2025. The city has pipe links to Seminole County and Sanford, but it uses them only for emergencies and repairs.

Lake Mary does not publish a hardness figure. For sprinkler days, the twice-a-week and once-a-week rules on our watering days page apply.

Sanford

Sanford draws from 17 Floridan wells feeding two plants, and the two plants handle sulfide differently. The city's drinking water FAQ says Plant No. 1 uses basic aeration, with an upgrade under way, while Plant No. 2 uses ozone followed by granular activated carbon. Water from both is chlorinated, and the 2026 report on 2025 data shows chlorine at 1.4 ppm.

Sanford has its own reclaimed water rules. Its watering brochure allows reclaimed customers three days a week all year, outside the midday hours. Drinking-water irrigation follows the district days. No hardness number is published.

Altamonte Springs

Altamonte Springs pumps from six wells, runs the water over aeration trays to remove hydrogen sulfide, and disinfects with chlorine at about 1.1 ppm. Its 2025 drinking water report also notes that fluoride is no longer added. Seminole County's Apple Valley and Druid Hills service areas buy their water from Altamonte.

On sewers, the state's Wekiwa springs plan notes that Altamonte makes every new building hook up to the city's wastewater system. Homes built earlier may still sit on a tank, so ask the city about your lot. Hardness is not published.

Winter Springs

Winter Springs is one of only two suppliers here that has put a hardness number in public. Its stated average is 150 mg/L. Divide by 17.1 and you get roughly 8.8 grains per gallon, though the city calls it 8. That counts as hard on the USGS scale. Eight wells feed three plants that use cascade aeration trays and chlorine, per the 2025 report.

The city also lists separate reports for a second system it calls Dovera. If your bill names Dovera, read that one instead. More on what the number means is on our hard water page.

Oviedo

Oviedo is the odd one out: it disinfects with chloramine, not chlorine. Ten Upper Floridan wells feed the West Mitchell Hammock plant, which uses forced-draft aeration designed to remove 99.9 percent of hydrogen sulfide. The 2024 report, the newest the city has posted, lists chloramine at 2.30 ppm.

That is worth knowing before you shop for a filter; see our whole-house filters page. Seminole County's Black Hammock service area buys Oviedo water, so it gets chloramine too. Hardness is not published.

Casselberry

Casselberry's own report could not be opened when we checked. What is on record comes from Seminole County, whose Sun Shadows area buys Casselberry water: it is aerated to remove hydrogen sulfide, filtered through granular activated carbon and chlorinated, according to the county's 2024 report. For the current figures and any hardness number, go to the city's utilities page or ask the city directly.

Orlando (OUC areas)

Orlando Utilities Commission pumps from the deeper Lower Floridan aquifer, which it has used since 1957, and treats with ozone to remove sulfide and cut the chlorine it needs. OUC's water quality page gives chlorine at about 1.0 ppm and says it does not use chloramine. Its hardness figure is 129 mg/L, near 7.5 grains per gallon by our math (OUC writes 7), and OUC it stopped adding fluoride on July 1, 2025.

Parts of north Orange County outside OUC are served by Orange County Utilities, which aerates and chlorinates and does not publish hardness; its 2025 report covers each system. On the septic side, Orange County's Wekiwa Springs septic-to-sewer program aims to convert almost 2,000 homes. Septic permits in Orange go through the county health department.

Unincorporated Seminole County

Seminole County Utilities serves much of the unincorporated county, and its yearly report is really 11 reports in one, each for a separate service area. Four areas have their own wells and plants: the Northeast and Northwest areas use ozone, the Southeast uses ozone plus aeration and carbon, and the Southwest is aerated. All four use chlorine. The rest buy water from Altamonte Springs, Oviedo, Sanford, Casselberry or a private utility.

The report's map shows which area you are in; we could not read that map, so we do not match streets to areas here. The newest county report we could reach covers 2024. County reclaimed customers may water two days a week all year, and the county requires backflow assemblies to be tested every year. See our reclaimed water and backflow pages.

Well and septic country: Geneva, Chuluota, Black Hammock

On the county's rural east and north edges, many homes pump their own water and treat their own wastewater. The USGS found that chloride in Upper Floridan water is lowest in the county's western recharge areas and near Geneva. Even so, nobody tests a private well for you. Florida DOH recommends testing for bacteria and nitrate every year and for lead every three years.

A new well gets its permit from DOH-Seminole, the county health office, not from the water district. Septic permits, including for repairs, come from that same office, although the state's environmental agency took charge of septic on July 1, 2021. No Florida rule makes owners of ordinary household tanks schedule inspections; EPA suggests pumping every 3 to 5 years and an inspection every 1 to 3 years. Our private wells and septic care pages go further. Seminole's watering ordinance covers private wells too.

Watering days, wherever you live

The schedule is the same across Seminole and north Orange on drinking water or a well. During daylight saving time, odd addresses water Wednesday and Saturday and even addresses Thursday and Sunday. The rest of the year it is once a week, Saturday for odd and Sunday for even, and in 2026 that switch comes on Sunday, November 1. Midday watering, 10 a.m. through 4 p.m., is off limits under the district's rules.

Where this came from

1. City of Longwood — 2025 Consumer Confidence Report and City of Lake Mary — 2025 Water Quality Report — wells, treatment, chlorine
2. City of Sanford — Annual Water Quality Report 2026, Drinking Water FAQ and watering brochure — plants, chlorine, reclaimed days
3. City of Altamonte Springs — 2025 Annual Drinking Water Quality Report — tray aeration, chlorine, fluoride
4. City of Winter Springs — 2025 report and archived potable water page — plants, hardness
5. City of Oviedo — 2024 Water Quality Report — chloramine, aeration
6. Seminole County Utilities — 2024 Water Quality Report (archived) and Cross-Connection Control Program (archived) — service areas, purchased water, Casselberry treatment, backflow testing
7. OUC — Water quality reports and FAQ and Orange County Utilities — 2025 Drinking Water Report — Orlando-area treatment and hardness
8. Orange County — Septic 2 Sewer and FDEP — Wekiwa and Rock Springs BMAP, 2018 — septic-to-sewer, Altamonte sewer policy
9. USGS — Floridan aquifer in Seminole County, Florida DOH — Private Well Water Testing and EPA — septic care — chloride near Geneva, well testing, pumping and inspection
10. SJRWMD — Watering restrictions, SJRWMD — aquifer and Seminole County watering rules (archived) — watering days, groundwater use, county reclaimed days