The anode rod is a sacrificial metal rod that corrodes preferentially to protect the steel tank. Replacing every 4-7 years is the highest-ROI Ruud maintenance task.
Replacement schedule
| Water hardness | Replace |
|---|---|
| Soft (under 7 gpg) | Year 5-7 |
| Medium (7-11 gpg) | Year 4-5 |
| Hard (over 11 gpg) | Year 3-4 |
Types
- Magnesium — factory standard. Can cause sulfur smell in well water
- Aluminum-zinc — eliminates sulfur smell
- Powered — electric impressed-current. Never replaced. $150-250
DIY replacement
- Turn off breaker/gas
- Close cold supply; open hot tap to relieve pressure
- Locate anode hex head on top of tank
- 1-1/16" socket on breaker bar (75-100 ft-lb)
- Unscrew, inspect
- Replace if rod consumed to less than ½" diameter or showing core wire
- Teflon tape on new threads; install
Cost
- Magnesium: $30-45
- Aluminum-zinc: $40-55
- Powered: $150-250
Bottom line
Replace every 4-7 years. Cheapest highest-ROI Ruud maintenance task.