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Water quality in Frisco, Plano, Allen and McKinney
Updated October 2, 2026 · Published by North Texas Water Solutions LLC
Frisco, Plano, Allen and McKinney all get their water from the same place, so the reasons homeowners add treatment are the same across the county.
- Same source for all four cities. Frisco, Plano, Allen and McKinney all buy treated water from the North Texas Municipal Water District (NTMWD), drawn mainly from Lavon Lake.
- Chloramine, not plain chlorine. NTMWD reported average chloramine residuals of 3.08 ppm (Wylie plant) and 3.61 ppm (Tawakoni plant) in 2024, against a 4.0 ppm limit. Standard carbon is slow to remove chloramine; catalytic carbon is made for it.
- Moderately hard. Total hardness measured 102–202 ppm as CaCO₃ at the Wylie plant in 2024, roughly 6–12 grains per gallon. That's enough to leave scale on fixtures, glass and water heaters.
- A chlorine smell every spring. Each March, NTMWD switches to free chlorine for about a month of system maintenance, so taste and smell are stronger. The water stays within safety standards.
Sources: NTMWD 2024 Water Quality Report; Community Impact: annual chlorine maintenance in March.
From the 2024 NTMWD report
| Measure | Wylie plant | Tawakoni plant | Leonard plant |
|---|---|---|---|
| Total hardness (ppm as CaCO₃) | 105–202 | 102–127 | 112–188 |
| Chloramine residual, average (ppm) | 3.08 | 3.61 | – |
| Chloramine residual, single-sample range (ppm) | 1.11–3.93 | 3.15–4.07 | – |
Source: NTMWD 2024 Water Quality Report. Limit for chloramine residual (MRDL): 4.0 ppm. Water sources named: Lavon Lake, Lake Texoma, Jim Chapman Lake, East Fork Water Reuse Project. All reports: NTMWD Water Quality Reports.
What each system addresses
| Issue you notice | Likely cause | Usual fix |
|---|---|---|
| Chlorine or "pool" taste and smell | Chloramine disinfectant; free chlorine each March | Whole-home catalytic carbon filtration |
| White scale on faucets, spotty glasses, short water heater life | Calcium and magnesium hardness | Water softener |
| Dry skin or hair after showering | Hardness and disinfectant together | Softener plus whole-home filter |
| Want better drinking and cooking water | Dissolved solids, taste | Reverse osmosis at the kitchen sink |
Frequently asked questions
Is tap water safe in Frisco, Plano, Allen and McKinney?
Yes. NTMWD water meets state and federal drinking water standards. People treat it at home for taste, smell, scale and appliance life, not to make unsafe water safe.
Why does my water smell like a pool in March?
Each spring, usually in March, NTMWD temporarily switches from chloramine to free chlorine for about a month of system maintenance. Taste and smell are stronger during that period; the water remains safe.
How hard is Collin County water?
NTMWD measured 102–202 ppm total hardness (as CaCO₃) at its Wylie plant in 2024, roughly 6–12 grains per gallon. Hardness varies by city and season; check your city's annual water quality report.
Where can I get my water tested?
Start with your city's free annual water quality report (Consumer Confidence Report), which lists hardness, disinfectant and other measured levels. Several companies in this guide also offer in-home water tests.