Water Hardness in 21771
Mount Airy, Maryland · Frederick County
Dataset updated March 9, 2026Matched to 5 water systemsTap readings can vary by utility zone, treatment, and plumbing. Methodology
How this ZIP reading is built
This ZIP reading is built from 5 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 21771
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 |
|---|---|---|---|
| New Design - Frederick County MD0100030 | surface water | 120 PPM Moderately HardUSGS estimate: 140 PPM | |
| City Of Frederick MD0100015 | surface water | 120 PPM Moderately HardUSGS estimate: 175 PPM | |
| Town Of Mount Airy MD0060007 | groundwater | 59 PPM Soft | |
| Pheasant Ridge Estates MD0060210 | groundwater | 59 PPM Soft | |
| Pleasant View Nursing Home MD0060211 | groundwater | 59 PPM Soft |
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 Mount Airy, MD (21771).
Frequently Asked Questions
Is the water hard in Mount Airy, MD (21771)?
The average water hardness in 21771 is 116 PPM (6.8 GPG), which is classified as slightly hard.
Do I need a water softener in 21771?
At 116 PPM, your water is relatively soft. A water softener is generally not necessary.
Is hard water in 21771 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 21771?
Zip code 21771 in Mount Airy, Maryland is served by 5 water systems.
Learn More About Your Water
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