Hard water in Des Peres, MO

Tap water hardness
263mg/L
15.4gpg
Very hard

Calculated from the utility's calcium and magnesium results · December 2020

MO typical
121 mg/L
Softener for 3 people
32k grain
Data
Calculated from utility data

Des Peres water measures 263 mg/L (15.4 gpg) of hardness, very hard by USGS standards. TapWaterData worked it out from the calcium and magnesium levels the local utility reports (December 2020).

Des Peres on the hardness scale, with nearby cities
060120180240300360+MO typical 121Eureka: 79 mg/LEureka 79Murphy: 104 mg/LMurphy 104St. Louis: 109 mg/LSt. Louis 109Chesterfield: 121 mg/LChesterfield 121Maryland Heights: 121 mg/LMaryland Heights 121Kirkwood: 130 mg/LKirkwood 130Ladue: 155 mg/LLadue 155Arnold: 212 mg/LArnold 212Town and Country: 234 mg/LTown and Country 234Ballwin: 242 mg/LBallwin 242Des Peres 263mg/L as calcium carbonate060120180240300360+MO 121Murphy: 104 mg/LMurphy 104Chesterfield: 121 mg/LChesterfie. 121Kirkwood: 130 mg/LKirkwood 130Ladue: 155 mg/LLadue 155Town and Country: 234 mg/LTown and C. 234Ballwin: 242 mg/LBallwin 242263 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 263 mg/L, Des Peres is 142 mg/L above the typical Missouri figure of 121. None of the 10 nearest cities we track has harder water. The range nearby runs from 79 mg/L in Eureka to 242 in Ballwin.

What 263 mg/L means at home

Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.

Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.

Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.

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

At 263 mg/L most of the trouble is scale, and only a few things deal with it.

Ion-exchange water softener

The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.

Salt-free conditioner

No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.

Reverse osmosis or carbon filter

Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.

Softener size for Des Peres

3 people × 75 gallons a day × 15.4 gpg = 3,465 grains a day. A 32,000-grain unit regenerates about every 9 days.

Size it for your household

EPA record for Des Peres's water system

We could not match Des Peres to a community water system in EPA's records. Your water bill or the yearly Consumer Confidence Report names the system and its ID.

Questions

Is Des Peres water hard?

Yes. It measures about 263 mg/L (15.4 grains per gallon), which the USGS classes as very hard.

What is the water hardness in Des Peres in grains per gallon?

About 15.4 gpg. One grain per gallon equals 17.1 mg/L, so 263 mg/L divided by 17.1 gives 15.4.

What size water softener do I need in Des Peres?

For 3 people using 75 gallons each per day, 15.4 gpg works out to about 3,465 grains a day. A 32,000-grain softener covers that with a regeneration about every 9 days.

Nearby cities

All 90 cities in Missouri

Hardness data: TapWaterData US Water Hardness (calculated from utility data, December 9, 2020), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.