Which US city has the softest water?

Asheville, North Carolina has the lowest estimate in this historical city comparison at just 0.3 GPG (5 PPM), sourced from Blue Ridge Mountain runoff through granitic rock. Portland, Oregon is a close second at 0.5 GPG (9 PPM) from the protected Bull Run Watershed.

Is soft water better for you?

Hardness alone does not establish health benefits or drinking-water safety. Lower hardness generally reduces mineral scale and soap deposits. Use your utility report and appropriate tests to assess other water-quality questions.

Why do some cities have naturally soft water?

Cities with soft water typically draw from surface water sources (rivers, reservoirs, snowmelt) in areas with granite, basalt, or other non-limestone geology. The Pacific Northwest and Northeast have the softest water because their water sources flow through igneous and metamorphic rock that doesn't dissolve calcium and magnesium.

Do I need a water softener if my city has soft water?

No. If your water is below 3.5 GPG (60 PPM), you don't need any water treatment for hardness. Cities like Portland, Seattle, and San Francisco have water soft enough that no softener, conditioner, or filter is needed to address hardness.

Can soft water cause any problems?

Very soft water (below 1 GPG) can be slightly more corrosive to older copper and lead pipes, which is why some soft-water cities add minerals back during treatment. Soft water can also feel "slippery" when washing with soap because there's no mineral residue to create friction.

20 US Cities With the Softest Water

Compare historical city estimates and selected utility reports in grains per gallon (GPG). See the source limitations below.

Quick Reference

Unit conversion: 1 GPG = 17.1 PPM

Soft threshold: <1 GPG

Low hardness: <3.5 GPG

#	City	GPG	PPM	Level	Water Source
1	Asheville, NC City of Asheville Water	0.3	5	Soft	Blue Ridge Mountain runoff (granitic)
2	Portland, OR Portland Water Bureau	0.5	9	Soft	Bull Run Watershed (protected snowmelt)
3	Tacoma, WA Tacoma Water	1	17	Slightly Hard	Green River (volcanic rock runoff)
4	Seattle, WA Seattle Public Utilities	1.2	20	Slightly Hard	Cedar River & Tolt River Watersheds
5	San Francisco, CA SFPUC	1.5	26	Slightly Hard	Hetch Hetchy Reservoir (Sierra Nevada granite)
6	Boston, MA MWRA	1.5	26	Slightly Hard	Quabbin & Wachusett Reservoirs
7	Atlanta, GA Atlanta Watershed	1.5	26	Slightly Hard	Chattahoochee River
8	New York City, NY NYC DEP	1.8	31	Slightly Hard	Catskill & Delaware Watersheds
9	Honolulu, HI Board of Water Supply	2	34	Slightly Hard	Volcanic basaltic aquifers
10	Washington DC, DC DC Water	2	34	Slightly Hard	Potomac River
11	Eugene, OR EWEB	2.1	36	Slightly Hard	McKenzie River (glacier-fed, volcanic rock)
12	Memphis, TN MLGW	2.7	46	Slightly Hard	Memphis Sands Aquifer (quartz sand)
13	Savannah, GA City of Savannah	2.8	48	Slightly Hard	Local sand-heavy Floridan Aquifer variant
14	Providence, RI Providence Water	2.9	50	Slightly Hard	Scituate Reservoir (metamorphic rock)
15	Hartford, CT MDC	3	51	Slightly Hard	Barkhamsted Reservoir
16	Burlington, VT Burlington DPW	3.1	53	Slightly Hard	Lake Champlain (Green Mountain snowmelt)
17	Nashville, TN Nashville Metro Water	3.3	57	Slightly Hard	Cumberland River
18	Charlotte, NC Charlotte Water	3.5	60	Moderately Hard	Mountain Island Lake & Lake Norman
19	Anchorage, AK AWWU	3.8	65	Moderately Hard	Eklutna Lake (glacier-fed)
20	Portland, ME Portland Water District	4	68	Moderately Hard	Sebago Lake (granite forest basin)

Why These Cities Have Soft Water

The softest water in the US follows a clear geographic pattern. Pacific Northwest cities like Portland and Seattle benefit from pristine mountain watersheds where water flows through volcanic basalt and granite — rocks that don't release calcium or magnesium.

Northeast cities including New York City, Boston, and Pittsburgh draw from protected reservoir systems in mountainous regions with similar igneous and metamorphic geology. NYC's water travels from the Catskill Mountains through one of the largest unfiltered surface water supplies in the country.

San Francisco benefits from the Hetch Hetchy Reservoir in Yosemite National Park — Sierra Nevada snowmelt filtered through granite, contributing to relatively low hardness. Hardness alone does not establish purity.

The common thread: surface water from high-elevation, non-limestone watersheds. These sources have minimal contact with the sedimentary rocks that dissolve calcium and magnesium into water.

Check Your Water Hardness

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Want to see the other end of the spectrum? View the 30-city hard-water comparison

Frequently Asked Questions

Historical research estimates. Newly checked city figures link to their municipal sources. Ranges are displayed where reported; sorting and category badges use their midpoints. These mixed references do not establish a national ranking of measured annual averages.