Water Hardness in Longmont, CO
Colorado · 3 zip codes · 23 matched water systems
City avg (weighted): 87 PPM
Dataset updated March 9, 202623 matched water systems in the city rollupIndividual systems and ZIPs can differ. Methodology
Is Longmont, CO Water Hard or Soft?
The displayed hardness for Longmont, CO is 90 PPM (5.3 GPG) from Boulder City Of, classified as slightly hard. The citywide weighted average is 87 PPM.
Water hardness is not a drinking-water safety score. It measures calcium and magnesium minerals, and address-level results can shift by pressure zone, supply blend, building plumbing, or private well.
How this city reading is built
This city reading is a weighted rollup across 23 matched water systems and 3 ZIP codes. Citywide readings are useful for comparison, but individual utility zones and ZIPs can differ.
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 in Longmont
These systems are matched to Longmont, CO. Citywide readings are useful for comparison, but the system serving a specific address may differ from the city average.
| Water System | Source | Hardness | Pop. Served |
|---|---|---|---|
| Boulder City Of CO0107152 | surface water | 90 PPM Slightly HardUSGS estimate: 151 PPM | |
| Greeley City Of CO0162321 | surface water | 80 PPM Slightly HardUSGS estimate: 162 PPM | |
| Longmont City Of CO0107485 | surface water | 90 PPM Slightly HardUSGS estimate: 165 PPM | |
| Erie Town Of CO0162255 | surface water | 90 PPM Slightly HardUSGS estimate: 158 PPM | |
| Lafayette City Of CO0107473 | surface water | 90 PPM Slightly HardUSGS estimate: 158 PPM |
Zip Codes in Longmont, CO
What This Means For You
Use this city 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 Longmont, CO.
Frequently Asked Questions
How hard is the water in Longmont, CO?
The citywide weighted average water hardness in Longmont, CO is 87 PPM (5.1 GPG), classified as slightly hard. This is based on 23 matched water systems. The gauge highlights Boulder City Of, a verified treated-water system, because individual systems can differ from the citywide average.
Do I need a water softener in Longmont, CO?
At 87 PPM, the citywide average is relatively soft. A water softener is generally not necessary.
Is hard water in Longmont, CO 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 Longmont, CO?
Longmont, Colorado is served by 23 matched water systems across 3 zip codes.
Learn More About Your Water
How to Test Water Hardness at Home
Compare free lookups, soap tests, test strips, liquid drop kits, and lab tests for measuring water hardness.
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Use the USGS water hardness scale to compare PPM, GPG, and mg/L levels from soft to very hard water.
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