Longview Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
groundwater
pH Level
7.5
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
134.7 mg/L
Est. Daily Cost
$0.40
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 Longview, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Longview | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Longview compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Longview, Washington | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | groundwater |
| Kelso, Washington | ≈ 180+ mg/L | 0 ppt | 🔴 Very Hard | mixed |
| Saint Helens, Oregon | 76 mg/L | 2.3 ppt | 🟡 Moderately Hard | reservoir |
| Salmon Creek, Washington | ≈ 120–179 mg/L | 2.7 ppt | 🟠 Hard | reservoir |
| Battle Ground, Washington | 68 mg/L | 3 ppt | 🟡 Moderately Hard | groundwater |
National Benchmark
How Longview compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Longview | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Longview's Water Unique?
Local geology and source profile
The Longview Water Department serves approximately 49,111 people across Longview and nearby areas in Cowlitz County, Washington. Water is sourced exclusively from four high-capacity groundwater wells — each rated at 4,000 gallons per minute — located at the city's water treatment plant on Industrial Way. The utility employs filtration, pre-oxidation with chlorine, and hypochlorite disinfection to meet all drinking water regulations; no surface water reservoirs or rivers are used in the supply.
Longview's groundwater draws from aquifers within the Lower Columbia River Basin, recharged by precipitation and river infiltration from the Columbia River and its tributaries. The geology features unconsolidated Quaternary alluvial and glacial deposits overlying Tertiary sedimentary rocks of the Cowlitz Formation, with influences from underlying Oligocene-Miocene volcanics. Dissolved calcium and magnesium from limestone and basalt weathering in the Cascade foothills impart a moderately mineralised character, elevating dissolved solids compared to softer surface-water systems in the region.
As moderately hard water, Longview's supply promotes moderate scale buildup in pipes, water heaters, and dishwashers, potentially reducing efficiency and lifespan if untreated. Boilers and faucets are susceptible to limescale trapping sediment. Regular vinegar descaling, installing scale-inhibiting filters, or using a water softener is recommended to improve soap efficiency and preserve skin moisture. The utility tests for 156+ contaminants; two exceed EPA health guidelines (within legal limits), while treatment includes filtration and chlorination to maintain regulatory compliance.
Geology & Source: Lower Columbia River Basin — Pleistocene glacial deposits over Tertiary Cowlitz Formation; sands and gravels with Oligocene-Miocene volcanic influence; basalt and limestone weathering yields moderately mineralised groundwater
Other Washington Water Reports
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Frequently Asked Questions
Is Longview's water safe to drink?
Do I need a water softener in Longview?
How does Longview compare to the USA average?
Data Sources & Methodology
Water quality data for Longview 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.