Hardest Water in Tennessee
20 cities ranked by water hardness. Collierville tops the list at 180 PPM.
Tennessee's water hardness varies significantly by city and water source. The state average across our database is 96 PPM, which is moderately hard. Some cities need treatment while others do not. 40% of cities we track in Tennessee have hardness above 120 PPM.
Collierville has the hardest water at 180 PPM (10.5 GPG). At this level, expect visible scale on faucets, reduced water heater efficiency, and higher soap usage. A salt-based water softener typically pays for itself within 12-18 months in energy and consumable savings. Johnson City has the softest water at just 15 PPM. No softener is needed.
| # | City | PPM | GPG | Level | Softener? |
|---|---|---|---|---|---|
| 1 | Collierville | 180 | 10.5 | Very Hard | Yes |
| 2 | Murfreesboro | 161 | 9.4 | Hard | Recommended |
| 3 | Franklin | 161 | 9.4 | Hard | Recommended |
| 4 | Clarksville | 140 | 8.2 | Hard | Recommended |
| 5 | Cookeville | 140 | 8.2 | Hard | Recommended |
| 6 | Brentwood | 135 | 7.9 | Hard | Recommended |
| 7 | Columbia | 120 | 7 | Hard | Recommended |
| 8 | Old Hickory | 120 | 7 | Hard | Recommended |
| 9 | Smyrna | 115 | 6.7 | Moderately Hard | Optional |
| 10 | Nashville | 110 | 6.4 | Moderately Hard | Optional |
| 11 | Hendersonville | 105 | 6.1 | Moderately Hard | Optional |
| 12 | Knoxville | 90 | 5.3 | Moderately Hard | Optional |
| 13 | Chattanooga | 82 | 4.8 | Moderately Hard | Optional |
| 14 | Jackson | 57 | 3.3 | Slightly Hard | No |
| 15 | Knoxville West | 55 | 3.2 | Slightly Hard | No |
| 16 | Germantown | 35 | 2 | Slightly Hard | No |
| 17 | Chattanooga Downtown | 35 | 2 | Slightly Hard | No |
| 18 | Memphis | 33 | 1.9 | Slightly Hard | No |
| 19 | Maryville | 25 | 1.5 | Slightly Hard | No |
| 20 | Johnson City | 15 | 0.9 | Soft | No |
Frequently Asked Questions
What is the average water hardness in Tennessee?
Across 20 cities in our database, the average water hardness in Tennessee is 96 PPM (5.6 GPG). This ranges from 15 PPM in Johnson City to 180 PPM in Collierville.
Do I need a water softener in Tennessee?
It depends on your city. 40% of Tennessee cities in our database (8 of 20) have hardness above 120 PPM where a softener provides measurable benefit. Check your specific city above.
Which Tennessee city has the softest water?
Johnson City has the softest water in Tennessee at 15 PPM (0.9 GPG). No water softener is needed at this level.
What causes hard water in Tennessee?
Hard water in Tennessee is caused by dissolved calcium and magnesium from the local geology. Regional geology varies, with some areas having limestone bedrock that adds minerals and others with granite or sandstone that produces softer water.