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Saint John has two very different waters. The Loch Lomond Drinking Water Treatment Facility, fed by the Loch Lomond and Latimer Lake watersheds, serves the east, north and south of the city and parts of the west side. Its treated water averaged 18.1 mg/L of hardness in two 2025 tests, which is soft. Since 2017, more than 3,000 customers on the west side get water from the South Bay wellfield instead, and that well water is very hard: 239 mg/L in the City's October 2024 test. Both waters are shown below. Our ranking uses Loch Lomond water, which most of the city drinks.
Data last reviewed October 24, 2026.
Saint John is tied for #1 softest of 31 cities in the Canadian Hard Water Report 2026. See the full ranking
In other units
Source: City of Saint John, Loch Lomond Drinking Water Treatment Facility, 2025 Annual Water Report (PDF). Data for: 2025, treated water, March and September tests. Checked October 24, 2026.
In other units
Source: City of Saint John, 2024 Annual Water Report, water quality appendix (PDF). Data for: October 24, 2024, one test of the wellfield water. Checked October 24, 2026.
Scale builds slowly with soft water. Odours, grease and detergent residue are the bigger issue, so clean the dishwasher and the washer about every two weeks.
At this hardness, grease and detergent residue are the bigger issue, so start with the dishwasher.
Only dishwashers with a built-in water softener have a hardness setting. Here is the setting for this water, worked out from each maker's own table.
| Brand | Loch Lomond Drinking Water Treatment Facility | South Bay wellfield |
|---|---|---|
| Bosch and ThermadorCanadian models with a softener. H:00 is off. | H:00 | H:04 |
| GaggenauSame ranges as Bosch. The display shows the °E band. | 0-8 | 16-20 |
| MieleSet in °dH. Below 5, Miele says no salt is needed. | 1 | 13 |
| Fisher & PaykelDishDrawer models with a softener. 0 is off. | 0 | 1 |
Most North American dishwashers, including Bosch models sold in the United States, have no water softener and no hardness setting. With those, use rinse aid and run a dishwasher cleaner once a month.
Sources: Bosch SHX78CC5UC manual, Thermador DWHD661EFP manual, Gaggenau DF481701 manual, Miele dishwasher manual (Canada), Fisher & Paykel DishDrawer guide
Softeners take hardness in US grains per gallon: the figure in mg/L divided by 17.12, rounded up.
| Brand | Loch Lomond Drinking Water Treatment Facility | South Bay wellfield |
|---|---|---|
| Nespresso Essenza PlusHardness level, and cups between descalings | Level 0 (4,000 cups) | Level 2 (2,000 cups) |
| Jura E8Hardness setting | 1 °dH | 13 °dH |
Sources: Nespresso Essenza Plus manual, Jura E8 manual, Breville Barista Touch manual, De'Longhi descaling FAQ, Keurig descaling page
Hard water leaves scale on the heating element and the drum, and more detergent residue behind.
Dissolves grease, detergent residue and limescale buildup, and removes odour-causing buildup.
Clears grease, limescale and odour buildup
Breaks down residue and odour-causing buildup inside your washer.
Removes odour and buildup from the drum and hoses
We use the U.S. Geological Survey scale, in mg/L as CaCO₃.
Utilities usually report hardness in mg/L as calcium carbonate (CaCO₃), which is the same as ppm. Dishwasher and softener manuals often use grains per gallon or German degrees instead. Here is how they convert:
It depends where you live. Loch Lomond water, which most of the city drinks, averaged 18.1 mg/L in 2025, which is soft. South Bay well water on part of the west side measured 239 mg/L in October 2024, which is very hard.
The City says the South Bay wellfield serves more than 3,000 customers on the west side, and Loch Lomond serves the rest, including some of the west side. It does not publish a street map, so ask Saint John Water if you are on the west side. Postal codes starting with E2M are split between the two, so they are not matched on this page.
On Loch Lomond water, less often than in harder-water cities: scale builds slowly, and grease, detergent residue and odours are the bigger issue. On South Bay well water, expect scale fast, and descale the coffee maker and kettle often.
For dishwashers with a built-in water softener, each maker's table gives: Loch Lomond Drinking Water Treatment Facility (most of the city): Bosch and Thermador H:00, Gaggenau 0-8, Miele 1, Fisher & Paykel 0. South Bay wellfield (part of the west side): Bosch and Thermador H:04, Gaggenau 16-20, Miele 13, Fisher & Paykel 1. Most North American dishwashers, including Bosch models sold in the United States, have no water softener and no hardness setting. With those, use rinse aid and run a dishwasher cleaner once a month.
Loch Lomond Drinking Water Treatment Facility (most of the city): 2 grains per US gallon (rounded up). South Bay wellfield (part of the west side): 14 grains per US gallon (rounded up).
Loch Lomond Drinking Water Treatment Facility (most of the city): 1.1 grains per US gallon, or 1.3 grains per imperial gallon. South Bay wellfield (part of the west side): 14.0 grains per US gallon, or 16.8 grains per imperial gallon.
City of Saint John, Loch Lomond Drinking Water Treatment Facility, 2025 Annual Water Report (PDF). Data for 2025, treated water, March and September tests. City of Saint John, 2024 Annual Water Report, water quality appendix (PDF). Data for October 24, 2024, one test of the wellfield water. We update this page when a new report comes out.
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