Water hardness in Marietta
2 gpg soft
Tap water in Marietta is soft: 2 gpg (33 mg/L · 1.9 °dH · 3.3 °fH).
Source: Cobb County-Marietta Water Authority - Annual Water Quality Information (2025 testing) (2025) · data checked 2026-10-23
Range across supply zones: 32–35 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| Quarles WTP | 1.9 | 32 | soft |
| Wyckoff WTP | 2.1 | 35 | soft |
Marietta Power and Water buys wholesale water from the Cobb County-Marietta Water Authority, which treats water from the Chattahoochee River and Lake Allatoona at two plants. Piedmont rivers carry few dissolved minerals, so the water is soft at 33.4 mg/L CaCO₃ (31.7–35.1 mg/L between the two plants). Scale is minimal.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 2 gpg |
|---|---|
| Utility | Marietta Power and Water (buys wholesale water from Cobb County-Marietta Water Authority) |
How Marietta compares
- Tap water in Marietta is 78 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1263 of 1372 in the United States (1 = hardest); 8 % of these cities have softer water.
- In Georgia it is number 3 of 9 cities; the regional median is 2 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Little or no limescale in kettles, water heaters or washing machines.
- Soap lathers easily; water does not dry skin or hair.
- Dishwasher: salt setting at minimum or off.
- No softener needed; a jug filter only changes taste.
How much salt will you use for softening?
No. Water this soft does not need softening.
Descale a coffee machine or kettle about every 6 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Marietta
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 2 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Marietta water hard or soft?
It is soft: 33 mg/L as CaCO₃ (2 gpg, 1.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Marietta 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 Marietta water?
2 gpg, equal to 1.9 °dH, 3.3 °fH or 33 mg/L calcium carbonate.
What dishwasher salt setting should I use in Marietta?
For 33 mg/L (1.9 °dH) check your manufacturer's table: level 0–1, usually no salt.
Do I need a water softener in Marietta?
No. With soft water a softener adds nothing.
Source
Source: Cobb County-Marietta Water Authority - Annual Water Quality Information (2025 testing) (2025). Method: figure published by the water supplier. Cobb County-Marietta Water Authority - Annual Water Quality Information (2025 testing) · Outdated figure? Tell us