Symptoms
- Drip or steady leak from the drain valve at the bottom of the tank
- Leak may have started after flushing the tank
- Valve may feel loose when touched
- No leak elsewhere on the tank
Likely causes
- CommonDrain valve not fully closed after flushing or drainingThese valves need a firm quarter to half turn to seal completely.
- CommonWorn washer or seal inside a compression-style drain valveRubber components wear out over years of occasional use.
- PossibleSediment lodged in the valve seat preventing a full sealDebris can get caught in the valve mechanism during flushing and prevent it from closing completely.
- PossibleCracked plastic valve body (common on lower-cost plastic drain valves)Plastic valves are more prone to cracking than brass ones over time.
What to do
- Try firmly closing the valve fully first, since an incompletely closed valve is the most common cause.
- If it still drips, try opening and closing it a few times to flush out any sediment caught in the valve seat.
- For a compression-style valve, an internal washer may be replaceable without removing the whole valve.
- If it's a simple threaded valve, it can often be replaced entirely by first partially draining the tank below the valve's level.
- Use thread sealant tape on the new valve's threads when installing a replacement.
- Consider upgrading to a brass ball-valve style drain valve, which tends to be more durable than the stock plastic ones.
Tools and parts
- Adjustable wrench
- Thread sealant tape
- Bucket
Water heater drain valve (brass ball valve)Search: “water heater brass drain valve replacement”
When to call a pro
If replacing the valve requires draining more of the tank than you're comfortable with, or the fitting is seized, a plumber can handle it quickly.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.