Louisville, CO water hardness

Tap water hardness
32mg/L
1.9gpg
Soft

Reported by Louisville City of · July 2025

CO typical
97 mg/L
EPA health violations since 2016
2
Data
Utility report

Louisville water measures 32 mg/L (1.9 gpg) of hardness, soft by USGS standards. The number comes from Louisville City of, dated July 2025.

Louisville on the hardness scale, with nearby cities
060120180240300360+CO typical 97Erie: 33 mg/LErie 33Boulder: 41 mg/LBoulder 41Broomfield: 46 mg/LBroomfield 46Lafayette: 91 mg/LLafayette 91Arvada: 93 mg/LArvada 93Thornton: 98 mg/LThornton 98Westminster: 100 mg/LWestminster 100Northglenn: 118 mg/LNorthglenn 118Federal Heights: 119 mg/LFederal Heights 119Shaw Heights: 127 mg/LShaw Heights 127Louisville 32mg/L as calcium carbonate060120180240300360+CO 97Erie: 33 mg/LErie 33Boulder: 41 mg/LBoulder 41Broomfield: 46 mg/LBroomfield 46Lafayette: 91 mg/LLafayette 91Arvada: 93 mg/LArvada 93Westminster: 100 mg/LWestminster 10032 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Louisville sits 65 mg/L below the typical Colorado figure of 97. None of the 10 nearest cities we track has softer water. The range nearby runs from 33 mg/L in Erie to 127 in Shaw Heights.

What 32 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Nothing, as far as hardness goes. At 32 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Louisville's water system

Louisville City of · PWSID CO0107487

2 health-based violations since 2016

Serves about 20,975 people from surface water.

Health-based
2
Monitoring or reporting
24
Open now
0
20162017201820192020202120222023202420252026Surface Water Treatment Rule'16'18'20'22'24'26Surface Water Treatment Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Surface Water Treatment Rulefiltration and disinfection22021Resolved

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Louisville water hard?

No. It measures about 32 mg/L (1.9 grains per gallon), which the USGS classes as soft.

What is the water hardness in Louisville in grains per gallon?

About 1.9 gpg. One grain per gallon equals 17.1 mg/L, so 32 mg/L divided by 17.1 gives 1.9.

Has the Louisville water system had EPA violations?

EPA records show 2 health-based violations for Louisville City of since 2016, involving Surface Water Treatment Rule. There were also 24 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 64 cities in Colorado

Hardness data: TapWaterData US Water Hardness (utility report, July 28, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.