Water Hardness in 57761
New Underwood, South Dakota · Pennington County
Dataset updated March 9, 2026Matched to 7 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology
How this ZIP reading is built
This ZIP reading is built from 7 matched water systems. When more than one system is matched, the displayed value is weighted toward larger known service populations when that data is available.
Hardness is a mineral-content reading, not a drinking-water safety rating. Use it for scale, appliance, and softener decisions; check your utility report or test your tap before sizing treatment equipment. See how we calculate local readings.
Water Systems Serving 57761
These are the systems matched to this ZIP code. The displayed ZIP value is weighted toward larger known service populations when population data is available.
| Water System | Source | Hardness | Pop. Served |
|---|---|---|---|
| Rapid City SD4600406 | surface water | 150 PPM Moderately HardUSGS estimate: 198 PPM | |
| Box Elder SD4600046 | groundwater | 150 PPM Moderately HardUSGS estimate: 558 PPM | |
| Rapid Valley Sanitary District SD4600274 | surface water | 150 PPM Moderately HardUSGS estimate: 810 PPM | |
| New Underwood SD4600224 | groundwater | 558 PPM Very Hard | |
| Viewfield Rural Water System SD4602287 | groundwater | 597 PPM Very Hard |
Nearby Zip Codes
What This Means For You
Use this ZIP reading as a local planning estimate, not a final treatment specification. Hardness can vary by utility zone, seasonal blend, private well, and building plumbing. Confirm your tap reading with a utility report or home hardness test before sizing equipment.
Know your water hardness?
If you've tested your water or have your utility's CCR report, share your reading to help us improve accuracy for New Underwood, SD (57761).
Frequently Asked Questions
Is the water hard in New Underwood, SD (57761)?
The average water hardness in 57761 is 155 PPM (9.1 GPG), which is classified as moderately hard.
Do I need a water softener in 57761?
With hardness of 155 PPM, a water softener is worth considering for homes in 57761.
Is hard water in 57761 safe to drink?
Water hardness itself is a mineral-content reading, not a drinking-water safety rating. Calcium and magnesium are naturally occurring minerals, but you should check your utility's Consumer Confidence Report for contaminant and compliance information.
How many water systems serve 57761?
Zip code 57761 in New Underwood, South Dakota is served by 7 water systems.
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