Water hardness in Tulsa
6.7 gpg moderately hard
Tap water in Tulsa is moderately hard: 6.7 gpg (115 mg/L · 6.4 °dH · 11.4 °fH).
Source: City of Tulsa Water and Sewer, FAQs About Water (water hardness) (2026) · data checked 2026-10-23
Range across supply zones: 89–140 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| gpg | mg/L | ||
|---|---|---|---|
| A.B. Jewell WTP | 8.2 | 140 | hard |
| Mohawk WTP | 5.2 | 89 | moderately hard |
Tulsa gets its water from Lakes Spavinaw and Eucha, owned by the city, and from Lake Oologah on the Verdigris River, treated at the Mohawk and A.B. Jewell plants. Hardness is 114.5 mg/L CaCO₃ across 2 supply zones (89–140 mg/L), so the tap depends on which plant serves you. Moderate scale builds up in kettles and heaters over time.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6.7 gpg |
|---|---|
| Utility | City of Tulsa Water and Sewer Department (Water Quality Assurance) |
How Tulsa compares
- Tap water in Tulsa is 26 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 939 of 1372 in the United States (1 = hardest); 32 % of these cities have softer water.
- In Oklahoma it is number 2 of 3 cities; the regional median is 6.7 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 Tulsa
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| 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 Tulsa water hard or soft?
It is moderately hard: 115 mg/L as CaCO₃ (6.7 gpg, 6.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Tulsa 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 Tulsa water?
6.7 gpg, equal to 6.4 °dH, 11.4 °fH or 115 mg/L calcium carbonate.
What dishwasher salt setting should I use in Tulsa?
For 115 mg/L (6.4 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Tulsa?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Tulsa Water and Sewer, FAQs About Water (water hardness) (2026). Method: figure published by the water supplier. City of Tulsa Water and Sewer, FAQs About Water (water hardness) · Outdated figure? Tell us