Manchester, NH water hardness
Manchester Water Works publishes an average hardness of 17.88 mg/L for its system, in its Manchester Water Works annual water quality report, Reporting Year 2022. On the USGS scale that is soft water.
The published figure, exactly as it appears
This is the hardness line transcribed from the source, with nothing added:
Total Hardness (ppm) 2022 17.88 16.7–18.8 A measure of dissolved minerals, primarily calcium and magnesium
Manchester Water Works, Manchester Water Works annual water quality report, Reporting Year 2022
Units as published: ppm. What kind of figure it is: an average with a range. Retrieved 2026-10-16.
Manchester 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 | 17.88 | 1 | mg/L published, gpg is our conversion |
| Low end of published range | 16.7 | 1 | mg/L published, gpg is our conversion |
| High end of published range | 18.8 | 1.1 | mg/L published, gpg is our conversion |
| Plotted on the scale above | 17.9 | 1 | 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: 17.9 ÷ 17.1 = 1 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 | Manchester Water Works |
|---|---|
| Public water system ID | NH1471010 |
| Service area as published | Manchester and portions of six surrounding communities, with service since expanded to portions of Salem, Hampstead, Atkinson and Plaistow (per the Reporting Year 2025 report). |
| Source water | Lake Massabesic, plus the Merrimack River via the Merrimack River Water Treatment Facility in Hooksett, activated in August 2023 (per the Reporting Year 2025 report). |
Provenance of every number on this page
| Source document | Manchester Water Works annual water quality report, Reporting Year 2022 |
|---|---|
| Source URL | https://salemnh.gov/DocumentCenter/View/4188/Manchester-Water-Quality-Report-2022 |
| Published by | Manchester Water Works (report republished by the Town of Salem, New Hampshire, a Manchester Water Works customer community) |
| Report year | 2022 |
| Year note | Covers testing performed between January 1 and December 31, 2022. |
| Retrieved | 2026-10-16 |
| Classification bands | USGS Water Science School, retrieved 2026-10-16 |
Notes the report forces on this page
- The 2022 report is the most recent Manchester Water Works report in which a Total Hardness line was found. The Reporting Year 2023, 2024 and 2025 reports were each read on 2026-10-16 and none of them carries a hardness line; the 2025 report lists calcium only (4.2 ppm average, 3.8–4.6 range) and the 2024 report states that a complete list of analytical results is available on request.
- The Merrimack River source was activated in August 2023, after the 2022 reporting period. A 2022 figure therefore predates a change in source water and may not describe water delivered today.
- Other report years checked on 2026-10-16: 2025 (no hardness line), 2024 (no hardness line), 2023 (no hardness line).
If you are sizing a softener for Manchester water
At 1 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 Manchester 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
- New York, NY 32 mg/L 2 gpg Soft
- Austin, TX 93 mg/L 5.4 gpg Moderately hard
- Denver, CO 105 mg/L 6.1 gpg Moderately hard
- Phoenix, AZ 237 mg/L 13.9 gpg Very hard
- Las Vegas, NV 280 mg/L 16 gpg Very hard
- San Antonio, TX 299.3 mg/L 17.5 gpg Very hard
- Indianapolis, IN 317 mg/L 19 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
- Boston, MA Massachusetts Water Resources Authority (MWRA), 16 mg/L (0.9 gpg)
- Portland, OR Portland Water Bureau, 9 mg/L (0.5 gpg)
- New York, NY New York City Department of Environmental Protection (NYC DEP), 32 mg/L (1.9 gpg)
- Austin, TX Austin Water, 93 mg/L (5.4 gpg)
All 10 verified systems How to find hardness in your own utility's report If you are on a well instead