Water Hardness in Oklahoma (OK)
Oklahoma has an average water hardness of 170 ppm (9.9 grains per gallon), which is classified as Moderately Hard . Water hardness at this level may cause noticeable scale buildup on fixtures and reduced soap lathering. Some Oklahoma households choose to install a water softener or conditioner for improved water quality, though it is not strictly necessary. Water hardness varies between cities — from 80 ppm in Tulsa to 240 ppm in Edmond.
Water Hardness by City in Oklahoma
The table below shows water hardness data for 8 cities in Oklahoma, sorted from hardest to softest. Click any city name for detailed information including water source, treatment recommendations, and estimated hard water costs.
| City | Hardness (PPM) | Grains/Gallon | Level | Water Source | pH | TDS | Utility |
|---|---|---|---|---|---|---|---|
| Edmond | 240 ppm | 14 gpg | Hard | Ground | 7.8 | 385 | City of Edmond Public Works |
| Enid | 230 ppm | 13.5 gpg | Hard | Ground | 7.8 | 370 | City of Enid |
| Lawton | 200 ppm | 11.7 gpg | Hard | Surface | 7.7 | 320 | City of Lawton Water Treatment |
| Stillwater | 175 ppm | 10.2 gpg | Moderately Hard | Surface | 7.6 | 275 | City of Stillwater Public Works |
| Norman | 160 ppm | 9.4 gpg | Moderately Hard | Surface | 7.6 | 250 | City of Norman Utilities |
| Oklahoma City | 100 ppm | 5.8 gpg | Slightly Hard | Surface | 7.3 | 155 | Oklahoma City Water Utilities Trust |
| Broken Arrow | 90 ppm | 5.3 gpg | Slightly Hard | Surface | 7.2 | 140 | City of Broken Arrow |
| Tulsa | 80 ppm | 4.7 gpg | Slightly Hard | Surface | 7.2 | 120 | City of Tulsa Water and Sewer |
Understanding Water Hardness in Oklahoma
Water Sources in Oklahoma
The majority of cities in Oklahoma draw their water from surface sources such as rivers, lakes, and reservoirs. Surface water generally contains fewer dissolved minerals than groundwater, which helps explain the overall hardness profile of the state. Cities that rely on surface water tend to have softer water because the water has less contact time with mineral-bearing rock formations underground.
Hardness Variation Across Oklahoma
Water hardness in Oklahoma ranges from 80 ppm in Tulsa to 240 ppm in Edmond — a difference of 160 ppm. This variation means that treatment recommendations differ significantly between cities. Residents of Edmond and other cities with hard water should seriously consider installing a water softener to protect their homes. At 240 ppm, the annual cost of hard water damage to appliances, plumbing, and increased cleaning product usage can easily exceed $11. Tulsa has the softest water in the state, though at 80 ppm it still contains some dissolved minerals.
Recommended Treatment for Oklahoma Water
Based on the average water hardness of 170 ppm in Oklahoma, a water softener is not strictly necessary, but some homeowners may prefer treated water. The most effective treatment options for Oklahoma's water hardness level include:
- Salt-Based Water Softener ($800 - $2,500) — Removes hardness minerals. Highly effective.
- Salt-Free Water Conditioner ($1,000 - $3,000) — Conditions water without removing minerals. Moderately effective.
- Reverse Osmosis System ($200 - $500) — Removes hardness minerals. Highly effective.
- Electronic Descaler ($150 - $400) — Conditions water without removing minerals. Moderately effective.
How Oklahoma Compares to Other States
Below is a comparison of Oklahoma with five states that have similar average water hardness levels. Understanding how your state compares can help you gauge whether your water is typical for the region or unusually hard or soft.
| State | Avg Hardness | Level | Cities |
|---|---|---|---|
| Oklahoma (OK) | 170 ppm | Moderately Hard | 8 |
| Colorado (CO) | 170 ppm | Moderately Hard | 9 |
| Idaho (ID) | 170 ppm | Moderately Hard | 8 |
| Missouri (MO) | 160 ppm | Moderately Hard | 8 |
| Montana (MT) | 180 ppm | Moderately Hard | 8 |
| Ohio (OH) | 160 ppm | Moderately Hard | 9 |
Find Your City's Water Hardness
Use our water hardness lookup tool to find your specific city in Oklahoma, or browse all 50 states to compare water hardness across the country. If your water is hard, visit our treatment solutions guide to find the right softener or conditioner for your home.