Short definition
A stop-and-waste valve is a globe- or ball-style shutoff with a small downstream “waste” port — a screw or plug — that opens to atmosphere when the main valve is closed, allowing the trapped downstream water to drain out by gravity. It’s the standard fitting for winterizing irrigation supply, exterior hose-bib feeds, and second-home properties.
What it is
The body looks like a normal shutoff valve, but with a small set screw or plug threaded into one side, oriented so it opens to the downstream side of the closed valve. Closing the main valve isolates the upstream side from the downstream side; opening the waste port lets air enter (or water exit) the downstream section. The trapped water drains out by gravity.
The small bleed port is usually 1/8 inch or 1/4 inch — enough to drain a residential supply line over minutes, not seconds.
The terminology overlaps with “drain-and-waste valve” — they’re the same fitting under two names. Some sources use one term exclusively, others use the other.
Why it matters to a homeowner
Winterization is the whole point. WA second-home and cabin culture (Hood Canal, San Juans, Whidbey, Methow Valley, Leavenworth, Olympic Peninsula) depends on stop-and-waste valves at the start of every supply line that runs through unconditioned space or to outdoor fixtures. The annual fall protocol:
- Close the main shutoff inside the house.
- Open every faucet to relieve pressure.
- Open every stop-and-waste valve at every low point.
- Watch the lines drain by gravity.
- Blow compressed air through hose bibs and exterior runs to clear horizontal standing water.
In spring, reverse: close the bleed ports, close the faucets, open the main shutoff, walk the system for leaks.
For irrigation systems, a stop-and-waste valve at the meter side of the backflow assembly allows full system winterization in one operation rather than multiple drain-down points.
Common variants and what it isn’t
- Stop-and-waste vs. drain-and-waste. Same concept, different name.
- Stop-and-waste vs. drain cock. Drain cock is just a drain port — no integrated shutoff. Stop-and-waste includes both.
- Stop-and-waste vs. hose bib. Hose bib has a service-spigot outlet for hose connection; stop-and-waste has a small bleed port that’s not designed for hose use.
Common failure modes
- Bleed port plugged with mineral or scale buildup — won’t drain when you need it. Diagnose during fall winterization, not during a January cold snap.
- Bleed port leaks past the screw plug — slow drip during normal service.
- Standard ball- or globe-valve failure modes for the main shutoff side.