About HardWaterHQ

HardWaterHQ answers one question cleanly: how hard is the water in your city? We publish hardness as grains per gallon (GPG) and parts per million (ppm), classify it into four tiers, and pair it with the water source, the serving utility, and a contaminant breakdown for every city we cover.

What we cover

For every city, you get:

• Hardness — GPG and ppm, with a Soft/Moderate/Hard/Very Hard tier.
• Why it's that way — the geology of the water source, in plain English.
• What it costs you — a research-anchored estimate of hard water's annual toll on appliances and cleaning.
• What's in it — contaminant detections with EPA legal limits (MCL) and Health Canada MACs, not just a bare count.
• What to do — an honest treatment recommendation, including "you probably don't need one."

Why some numbers deserve a grain of salt

Search water hardness for a smaller city and you'll often find two sites listing different figures — or showing a number for a city whose utility has never published one. Hardness isn't a regulated health parameter, so no law requires a utility to report it. Where a utility stays quiet, other sites silently fill the gap.

Most of the time those figures aren't measured. They're estimated from a neighboring system, copied from another aggregator, or fabricated to look authoritative. We'd tell you to take them with a grain of salt — which is fitting, because the calcium and magnesium carbonate that make water "hard" are, literally, salts (a "10-grain" softener is named for the grains of dissolved mineral salt it removes).

What we do instead

Our standard is simple: a number is only as good as the document it traces to.

• Primary sources only. We cite a utility's own water-quality report (CCR), a state or provincial health department, or USGS/EWG data — never a vendor or a water-softener lead-gen site.
• We read the actual report. Before publishing a figure we open the document and confirm hardness (or calcium + magnesium) is actually in it.
• "Not published" beats a guess. If a utility genuinely omits hardness, we say so and explain how to check your own water — rather than hand you an estimated number.
• Every number is traceable. Each page links its primary source right at the top (and again in the Sources section), so you can verify the exact figure yourself.
• Kept current. Every page shows the report year its data comes from.

The rule we ship by: if you see a number on HardWaterHQ, you can click straight through to where it came from. If we can't trace it, we don't publish it.

Our methodology

Every number on HardWaterHQ is sourced, not estimated. Every city page carries a clickable link to its primary source. The priority order for any city is:

1. Utility-reported hardness — taken from the primary municipal water-quality report (Consumer Confidence Report / Annual Water Quality Report). This is the gold standard and the only source we ship without caveats.
2. USGS and EWG Tap Water Database — used for contaminant data and to cross-check hardness where utility figures are unclear.
3. Health Canada and provincial datasets — for Canadian cities, contaminant levels are sourced from municipal reports and provincial water datasets, and compared against Health Canada MACs rather than U.S. EPA limits.

Where a utility publishes calcium and magnesium concentrations, hardness is derived from those values and noted as computed. U.S. contaminant figures are compared against EPA Maximum Contaminant Levels (MCLs); Canadian figures against Health Canada Maximum Acceptable Concentrations (MACs). Every city on the site is fully cited — we don't ship a number without a source.

The hardness scale we use

We use the widely accepted USGS-classified ranges:

• Soft — below 3.5 GPG (0–60 ppm)
• Moderate — 3.5 to 7.0 GPG (60–120 ppm)
• Hard — 7.0 to 10.5 GPG (120–180 ppm)
• Very Hard — above 10.5 GPG (180+ ppm)

Where the data comes from

Our figures draw on four primary source families:

• Municipal water-quality reports (CCRs) — the authoritative local source for hardness and contaminants.
• USGS — Water Science School — hardness classification and regional geology.
• EWG — Tap Water Database — contaminant detections and guideline comparisons.
• U.S. EPA and Health Canada — the legal limits (MCL / MAC) against which contaminant levels are measured.

Full detail, including licensing notes, is on our Sources page.

Independent of the companies we link to

HardWaterHQ is an independent reference. We recommend water softeners, filters, and test kits, but our hardness data and editorial recommendations are never influenced by affiliate relationships. Product decisions are made first on merit, then monetized where it doesn't distort the answer. See the affiliate disclosure for the full policy.

Our accuracy standard

We treat a wrong number as worse than no number. If a water source or utility can't be verified against that utility's published materials, we either label it clearly or don't publish the specific claim. Where you spot something that looks off, we want to hear about it — every correction gets verified against the primary source and fixed.

About us

HardWaterHQ is part of Gravison Group. The site's data and editorial are overseen by Jarrod Gravison, our editor and data lead. Questions, corrections, or a city you'd like added? Contact us.