How does Hillsboro's water compare to the national average?

The USA national average is 151 mg/L. Hillsboro (≈ 120–179 mg/L) is 1 mg/L softer than average.

Hillsboro Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.2

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

97 mg/L

Est. Daily Cost

$0.40

energy & soap waste

Source: See methodology section below · Updated 2026

hard~120–179 mg/LHard · est.

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 Hillsboro, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Hillsboro	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 Hillsboro compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Hillsboro, Oregon	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Cornelius, Oregon	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Forest Grove, Oregon	≈ 0–60 mg/L	0 ppt	🟢 Soft	reservoir
Aloha, Oregon	≈ 120–179 mg/L	2.1 ppt	🟠 Hard	groundwater
Bethany, Oregon	≈ 0–60 mg/L	2.2 ppt	🟢 Soft	reservoir

National Benchmark

How Hillsboro compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Hillsboro	≈ 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 Hillsboro's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 97 mg/LpH: 7.2

Hillsboro Water serves over 110,000 residents across three community water systems in Washington County, Oregon: the In-Town Water System (west of Cornelius Pass Road and south of Highway 26), the Upper-System Water System (western Washington County along Highway 47 from Dilley to Cherry Grove), and the Butternut Creek Water System (off SE Butternut Creek Parkway). The primary water source is the Bull Run Watershed, located in the Cascade Mountains and managed by the Portland Water Bureau. During peak demand, the system is supplemented by the Columbia South Shore Wellfield — 25 wells drawing from 4 aquifers with a capacity near 100 million gallons per day — and the Joint Water Commission, which blends water from Hagg Lake (Scoggins Reservoir) and the Tualatin River.

The Bull Run Watershed flows over volcanic rock formations and ancient lava beds in the Cascade Mountains, naturally picking up dissolved minerals as water transits these formations. The Columbia South Shore Wellfield draws from four distinct aquifers, with Columbia River water contributing additional mineral content from its multi-formation journey. The Joint Water Commission blends Hagg Lake and Tualatin River waters, adding further mineral variation. The combination of volcanic geology and multiple water sources produces a moderately hard supply overall.

At moderately hard levels, Hillsboro residents may notice mineral buildup on fixtures, reduced soap effectiveness, and scale accumulation in water heaters, dishwashers, washing machines, and hot water systems over time. Regular descaling and appliance maintenance is recommended. While a water softener is not essential for health, many households install one to reduce spotting on dishes and extend appliance lifespan. Hillsboro Water treats the supply with chlorine and ammonia for disinfection and adjusts pH to reduce pipe corrosiveness; all detected contaminants including disinfection byproducts, chromium-6, and nitrates remain within legal limits.

Geology & Source: Bull Run Watershed Cascade Mountains volcanic rock and ancient lava beds — low-mineral surface water; Columbia South Shore Wellfield (4 aquifers) and Tualatin River via Joint Water Commission add dissolved minerals; blended supply produces moderate

Other Oregon Water Reports

Cornelius

≈ 120–179 mg/L

🟠 Hard

Forest Grove

≈ 0–60 mg/L

🟢 Soft

Aloha

≈ 120–179 mg/L

🟠 Hard

Bethany

≈ 0–60 mg/L

🟢 Soft

Report an Issue

Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Hillsboro's water safe to drink?

Yes. Hillsboro's water meets all federal safety standards. The hardness is ≈ 120–179 mg/L (Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Hillsboro?

At ≈ 120–179 mg/L (Hard), Hillsboro's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 20%.

How does Hillsboro compare to the USA average?

The USA national average is 151 mg/L. Hillsboro (≈ 120–179 mg/L) is 1 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Hillsboro is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

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.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

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.

Measured

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.

Modelled

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.

Calculated

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.