Reliance tanks (and the rest of the AO Smith budget family) ship with a plastic drain valve that often seizes within 3-5 years. The plastic handle breaks, the valve seat hardens, or the threads strip during force. The single best upgrade you can make to your Reliance tank is replacing the plastic drain valve with a ¾" brass ball valve after the first annual flush.
Why the plastic valve fails
- Polypropylene handle becomes brittle from repeated thermal cycling
- Mineral scale builds inside the valve seat
- The compression fit at the tank thread loosens over years
- Once seized, attempting force often cracks the valve body, dumping a tank of hot water
What you need
- ¾" brass full-port ball valve (NPT male × hose thread female, or NPT male × NPT female + hose adapter)
- Pipe wrench (2)
- Teflon tape or pipe dope
- Bucket
Replacement procedure (do this after a full annual flush)
- Turn off heat source and cold water inlet
- Drain the tank completely via the existing drain valve (this is also your annual flush)
- Once empty, remove the plastic drain valve: hold the tank fitting with one pipe wrench, unscrew the plastic valve with the other
- Clean the tank threads
- Apply Teflon tape (4-5 wraps clockwise) to the brass valve threads
- Install the brass valve, hand-tight plus 1-2 turns with a wrench
- Attach a hose adapter to the outlet end if your brass valve has NPT female threads
- Close the brass valve handle
- Restore cold inlet; refill tank; check for leaks at the new valve
- Restore heat source
Benefits of the brass upgrade
- Never seizes — full-port ball valves last decades
- Faster drain — full-port ¾" vs restricted plastic seat
- Hose threads usable without thread damage
- Replaceable: if it ever fails, you can swap without replacing the heater
Cost
- ¾" brass ball valve (NPT × hose): $12-18
- Hose adapter (if needed): $3-5
- Teflon tape: $2
- Plumber labor: $40-80 if hired (often bundled with annual flush)
Bottom line
Best $15-20 upgrade on the Reliance tank. Do it after your first annual flush and you\'ll never fight a stuck drain valve again. Same logic applies to State, Whirlpool, and AO Smith family budget tiers — they all ship with the same plastic valve.