How hard is the water in Poolesville, MD?

Tap water hardness
84mg/L
4.9gpg
Moderately hard

Reported by Town of Poolesville · September 2025

MD typical
105 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
Utility report

Poolesville water measures 84 mg/L (4.9 gpg) of hardness, moderately hard by USGS standards. The number comes from Town of Poolesville, dated September 2025.

Poolesville on the hardness scale, with nearby cities
060120180240300360+MD typical 105Fort Meade: 4 mg/LFort Meade 4Westminster: 62 mg/LWestminster 62Columbia: 74 mg/LColumbia 74Fairwood: 78 mg/LFairwood 78Ellicott City: 82 mg/LEllicott City 82Brunswick: 84 mg/LBrunswick 84Frederick: 105 mg/LFrederick 105Takoma Park: 110 mg/LTakoma Park 110Mount Airy: 131 mg/LMount Airy 131Urbana: 132 mg/LUrbana 132Poolesville 84mg/L as calcium carbonate060120180240300360+MD 105Columbia: 74 mg/LColumbia 74Brunswick: 84 mg/LBrunswick 84Frederick: 105 mg/LFrederick 105Takoma Park: 110 mg/LTakoma Park 110Mount Airy: 131 mg/LMount Airy 131Urbana: 132 mg/LUrbana 13284 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

At 84 mg/L, Poolesville is 21 mg/L below the typical Maryland figure of 105. Of the 10 nearest cities we track, 5 have softer water and 4 have harder. The range nearby runs from 4 mg/L in Fort Meade to 132 in Urbana.

What 84 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Poolesville

3 people × 75 gallons a day × 4.9 gpg = 1,107 grains a day. A 24,000-grain unit regenerates about every 21 days.

Size it for your household

EPA record for Poolesville's water system

Town of Poolesville · PWSID MD0150002

No health-based violations since 2016

Serves about 6,005 people from surface water.

Health-based
0
Monitoring or reporting
2
Open now
0

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 Poolesville water hard?

Somewhat. It measures about 84 mg/L (4.9 grains per gallon), which the USGS classes as moderately hard.

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

About 4.9 gpg. One grain per gallon equals 17.1 mg/L, so 84 mg/L divided by 17.1 gives 4.9.

What size water softener do I need in Poolesville?

For 3 people using 75 gallons each per day, 4.9 gpg works out to about 1,107 grains a day. A 24,000-grain softener covers that with a regeneration about every 21 days.

Has the Poolesville water system had EPA violations?

EPA records show no health-based violations for Town of Poolesville since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 24 cities in Maryland

Hardness data: TapWaterData US Water Hardness (utility report, September 2, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.