Water hardness in Cookeville
4.5 gpg moderately hard
Tap water in Cookeville is moderately hard: 4.5 gpg (77 mg/L · 4.3 °dH · 7.7 °fH).
Source: City of Cookeville 2026 Consumer Confidence Report (2025 data) (2025) · data checked 2026-11-02
The City of Cookeville reports 76.6 mg/L as CaCO3 in its 2026 Consumer Confidence Report, which covers 2025 data. That is in the moderate band, so scale builds up slowly on kettles and fixtures. The report gives a single value and no range, so seasonal swings are not documented here.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 4.5 gpg |
|---|---|
| Utility | City of Cookeville Water Quality Control |
How Cookeville compares
- Tap water in Cookeville is 51 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1122 of 1372 in the United States (1 = hardest); 18 % of these cities have softer water.
- In Tennessee it is number 4 of 9 cities; the regional median is 3.8 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Cookeville
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Cookeville water hard or soft?
It is moderately hard: 77 mg/L as CaCO₃ (4.5 gpg, 4.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Cookeville safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Cookeville water?
4.5 gpg, equal to 4.3 °dH, 7.7 °fH or 77 mg/L calcium carbonate.
What dishwasher salt setting should I use in Cookeville?
For 77 mg/L (4.3 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Cookeville?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Cookeville 2026 Consumer Confidence Report (2025 data) (2025). Method: figure published by the water supplier. City of Cookeville 2026 Consumer Confidence Report (2025 data) · Outdated figure? Tell us