Aurora, CO water hardness
Aurora Water (City of Aurora) publishes an average hardness of 113 mg/L for its system, in its City of Aurora, Colorado Water Quality Report 2025, data from January 1, 2024 to December 31, 2024. On the USGS scale that is moderately hard water, though the utility's own range crosses more than one class — it spans soft, moderately hard and hard water from end to end.
The published figure, exactly as it appears
This is the hardness line transcribed from the source, with nothing added:
Units SMCL Average Level Detected Range Sample Date […] Hardness (as CaCO3) ppm N/A 113 56 to 154 Daily Erosion of natural deposits
Aurora Water (City of Aurora), City of Aurora, Colorado Water Quality Report 2025, data from January 1, 2024 to December 31, 2024
Units as published: ppm. What kind of figure it is: an average with a range. Retrieved 2026-10-26.
Aurora hardness in mg/L and grains per gallon
Water-quality reports use mg/L (identical to ppm). Softener instructions and plumbing specifications use grains per gallon. Both are below. Where a figure is our arithmetic rather than the utility's own number, it says so.
| Figure | mg/L (ppm) | Grains per gallon | Whose number |
|---|---|---|---|
| Published average | 113 | 6.6 | mg/L published, gpg is our conversion |
| Low end of published range | 56 | 3.3 | mg/L published, gpg is our conversion |
| High end of published range | 154 | 9 | mg/L published, gpg is our conversion |
| Plotted on the scale above | 113 | 6.6 | published average; the gpg here is our conversion at 17.1, so it can differ slightly from a utility’s own rounded gpg figure |
The conversion, both ways: gpg = mg/L ÷ 17.1 and mg/L = gpg × 17.1. Worked for this system: 113 ÷ 17.1 = 6.6 gpg. The converter does °dH and °f as well, and why the factor is 17.1 explains where the number comes from.
What this figure does not tell you
Service area and source water
| Utility | Aurora Water (City of Aurora) |
|---|---|
| Public water system ID | CO0103005 |
| Service area as published | The City of Aurora's public water system (CO0103005), treated at the Thomas J. Griswold, Charles A. Wemlinger and Peter D. Binney water purification facilities. The report does not break hardness down by facility. Aurora Water is a separate utility from Denver Water; this page does not describe Denver Water customers. |
| Source water | Surface water from the South Platte, Arkansas and Colorado river basins stored in 12 reservoirs and lakes, plus wells, per the report. |
Provenance of every number on this page
| Source document | City of Aurora, Colorado Water Quality Report 2025, data from January 1, 2024 to December 31, 2024 |
|---|---|
| Source URL | https://www.buckley.spaceforce.mil/Portals/13/Aurora%20CCR%202024%20-%202025.pdf |
| Published by | City of Aurora (Aurora Water), read from the copy hosted on Buckley Space Force Base's website |
| Report year | 2024 |
| Year note | The report is titled 2025 and states that all data are from January 1 to December 31, 2024. Hardness sits in its “Secondary Contaminants/Other Unregulated Monitoring” table, sampled daily. Aurora's newer report (2026, 2025 data) is linked from auroragov.org/CCR but could not be fetched on the retrieval date; it is listed under blocked sources and not used. |
| Retrieved | 2026-10-26 |
| Classification bands | USGS Water Science School, retrieved 2026-10-16 |
Notes the report forces on this page
- This is the City of Aurora's own 2025 report, read from the copy hosted on Buckley Space Force Base's website (the document itself does not mention Buckley), because the city's own link (auroragov.org/CCR) now points to the newer 2026 report, which could not be fetched. The figures describe 2024.
- The same table carries a second row, “Hardness-CA (as CaCO3) ppm N/A 95.9 49.6 to 185 Weekly”, which is calcium hardness sampled weekly. Its published maximum (185) is higher than the total-hardness maximum (154). Both rows are reproduced as published and neither is adjusted; this page uses the total-hardness row.
- The published range crosses three USGS classes: 56 ppm is soft, 113 ppm is moderately hard and 154 ppm is hard.
If you are sizing a softener for Aurora water
At 6.6 gpg, the sizing arithmetic starts from your household's water use, not from the hardness alone. The calculator below is pre-filled with this system's figure and every other input is an editable assumption.
Whether a softener is worth installing at this hardness is a judgement, not arithmetic, and it is not one this site makes for you. Nothing here has been tested by the author.
Where Aurora sits against other verified systems
- Portland, OR 9 mg/L 0.5 gpg Soft
- Boston, MA 16 mg/L 1 gpg Soft
- Manchester, NH 17.9 mg/L 1 gpg Soft
- Seattle, WA 19.1 mg/L 1.1 gpg Soft
- Raleigh, NC 25 mg/L 1.47 gpg Soft
- New York, NY 32 mg/L 2 gpg Soft
- Charlotte, NC 32 mg/L 1.9 gpg Soft
- Memphis, TN 46 mg/L 2.7 gpg Soft
- Norfolk, VA 48 mg/L 2.8 gpg Soft
- Anchorage, AK 56 mg/L 3.3 gpg Soft
- Virginia Beach, VA 56 mg/L 3.3 gpg Soft
- Oakland, CA 68.4 mg/L 4 gpg Moderately hard
- Nashville, TN 77.3 mg/L 4.5 gpg Moderately hard
- Sacramento, CA 83 mg/L 4.9 gpg Moderately hard
- Fresno, CA 89.3 mg/L 5.2 gpg Moderately hard
- Saint Paul, MN 90 mg/L 5 gpg Moderately hard
- Austin, TX 93 mg/L 5.4 gpg Moderately hard
- Minneapolis, MN 94 mg/L 5.5 gpg Moderately hard
- Washington, DC 95 mg/L 5.6 gpg Moderately hard
- Baltimore, MD 97.5 mg/L 5.7 gpg Moderately hard
- Birmingham, AL 98 mg/L 5.7 gpg Moderately hard
- Kansas City, MO 100 mg/L 5.8 gpg Moderately hard
- Denver, CO 105 mg/L 6.1 gpg Moderately hard
- Detroit, MI 107 mg/L 6.3 gpg Moderately hard
- Aurora, CO 113 mg/L 6.6 gpg Moderately hard
- Tulsa, OK 114.5 mg/L 6.7 gpg Moderately hard
- Louisville, KY 115 mg/L 6.7 gpg Moderately hard
- Columbus, OH 120 mg/L 7 gpg Moderately hard
- Cleveland, OH 120 mg/L 7 gpg Moderately hard
- Philadelphia, PA 125 mg/L 7.3 gpg Hard
- Ann Arbor, MI 126 mg/L 7.4 gpg Hard
- Cincinnati, OH 133 mg/L 7.8 gpg Hard
- Chicago, IL 134.5 mg/L 7.9 gpg Hard
- Houston, TX 135.5 mg/L 7.9 gpg Hard
- Milwaukee, WI 137 mg/L 8.01 gpg Hard
- St. Louis, MO 138 mg/L 8.1 gpg Hard
- Grand Rapids, MI 142 mg/L 8.3 gpg Hard
- Fort Worth, TX 145 mg/L 8.5 gpg Hard
- Spokane, WA 159 mg/L 9.3 gpg Hard
- Honolulu, HI 162.5 mg/L 9.5 gpg Hard
- Wichita, KS 170 mg/L 9.9 gpg Hard
- Omaha, NE 170 mg/L 10 gpg Hard
- Los Angeles, CA 192 mg/L 11.2 gpg Very hard
- Lincoln, NE 192 mg/L 11.2 gpg Very hard
- Riverside, CA 197 mg/L 12 gpg Very hard
- Tampa, FL 220 mg/L 12.9 gpg Very hard
- Phoenix, AZ 237 mg/L 13.9 gpg Very hard
- Mesa, AZ 239.4 mg/L 14 gpg Very hard
- Round Rock, TX 258 mg/L 15.1 gpg Very hard
- Pflugerville, TX 267 mg/L 15.6 gpg Very hard
- San Diego, CA 276 mg/L 16 gpg Very hard
- Las Vegas, NV 280 mg/L 16 gpg Very hard
- Chandler, AZ 282.2 mg/L 16.5 gpg Very hard
- San Antonio, TX 299.3 mg/L 17.5 gpg Very hard
- Anaheim, CA 300 mg/L 18 gpg Very hard
- Henderson, NV 304 mg/L 18 gpg Very hard
- Indianapolis, IN 317 mg/L 19 gpg Very hard
- Madison, WI 324.9 mg/L 19 gpg Very hard
- Scottsdale, AZ 352.5 mg/L 20.6 gpg Very hard
- Salt Lake City, UT 353.5 mg/L 20.7 gpg Very hard
mg/L as calcium carbonate. Each classification band is drawn the same width, so the axis is not linear in mg/L.
Systems with similar published hardness
- Tulsa, OK City of Tulsa Water and Sewer, 114.5 mg/L (6.7 gpg)
- Louisville, KY Louisville Water Company, 115 mg/L (6.7 gpg)
- Detroit, MI Detroit Water and Sewerage Department, 107 mg/L (6.3 gpg)
- Columbus, OH City of Columbus Division of Water, 120 mg/L (7 gpg)
All 60 verified systems How to find hardness in your own utility's report If you are on a well instead