Derby Water Hardness & Quality Report (2026)
Water Hardness
180+ mg/L
Very Hardestimated · not lab-verified
Source
reservoir
pH Level
7.7
neutral = 7.0
Lead
0.003 mg/L
✓ Below action level
TDS
141 mg/L
Est. Daily Cost
$0.91
energy & soap waste
Source: See methodology section below · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Derby, your appliances are currently losing 45% efficiency due to mineral buildup.
| Appliance | In Derby | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.7 yrs | 8.5 yrs | -45% |
| Washing Machine | 6.6 yrs | 12 yrs | -45% |
| Water Heater | 8.3 yrs | 15 yrs | -45% |
Regional Water Comparison
How Derby compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Derby, Kansas | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | reservoir |
| Haysville, Kansas | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | groundwater |
| Wichita, Kansas | ≈ 120–179 mg/L | 10 ppt | 🟠 Hard | reservoir |
| Andover, Kansas | ≈ 120–179 mg/L | 2.8 ppt | 🟠 Hard | groundwater |
| Winfield, Kansas | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | reservoir |
National Benchmark
How Derby compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Derby | ≈ 180+ mg/L | 🔴 High |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Derby's Water Unique?
Local geology and source profile
The City of Derby Public Water System supplies drinking water to over 25,000 residents in Derby, Kansas, located in Sedgwick County south of Wichita. Water is sourced from wells tapping the Equus Beds Aquifer, with treatment handled at city-operated facilities. The system is a groundwater-only utility, with no named reservoirs or rivers directly serving it. The utility complies with EPA standards as documented in the 2024 Consumer Confidence Report available on derbyks.gov, and a Source Water Assessment is referenced for additional supply details.
The supply originates from the Arkansas River watershed, where surface flows infiltrate into the Equus Beds Aquifer, a major unconfined aquifer spanning central Kansas. Key geological features include Pleistocene sands, gravels, and silts overlying Permian shales and limestones of the Wellington Formation, with deeper connections to the Dakota Formation (Cretaceous). This carbonate-rich geology yields a very hard supply, as dissolved calcium and magnesium elevate mineral content and total dissolved solids throughout the aquifer system.
Very hard water in Derby leads to significant scale buildup in pipes, water heaters, dishwashers, washing machines, and coffee makers, reducing efficiency and lifespan. Showers may leave a filmy residue on skin and hair, while laundry requires more detergent. Maintenance tips include regular vinegar descaling for appliances, installing sediment filters, and flushing water heaters biannually. A whole-house water softener is strongly recommended to mitigate damage and extend appliance life. The 2024 Consumer Confidence Report confirms no violations; treatment involves disinfection with chlorine and filtration at wells to address groundwater minerals.
Geology & Source: Equus Beds Aquifer — Pleistocene sands and gravels overlying Ogallala Formation; carbonate-rich sediments with Wellington Formation (Permian) limestone and dolomite dissolve freely, yielding very hard water
Other Kansas Water Reports
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Frequently Asked Questions
Is Derby's water safe to drink?
Do I need a water softener in Derby?
How does Derby compare to the USA average?
Data Sources & Methodology
Water quality data for Derby is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
Water Hardness
Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
TDS — Total Dissolved Solids
Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.
PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances
EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.
Lead
Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.
Appliance Lifespan
Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.