A stop-and-waste valve is a shutoff with a small drain port: close it, open the port, and the pipe past the valve can drain or let air in. Plumbers put them on lines to outdoor faucets, sprinklers and seasonal buildings so those runs can be emptied before a freeze. It only drains pipe that slopes back to it; low spots and connected equipment can still hold water. Install it with the drain on the side you want to empty, and choose by pipe size and end type, like the 3/4-inch push-to-connect SharkBite 24635LF below.
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Choose the valve as one part of the drainage and service plan. A small drain port cannot compensate for an unsuitable location or water trapped elsewhere.
What stop and waste actually describes
A stop-and-waste valve combines a water shutoff with a way to drain or vent a selected part of the line. Identify the exact design before assuming how its drain operates.
Watts’s LFSWT description (watts.com) gives a conventional example: its drain cock allows the downstream line to drain or vent when the main valve is off.
That does not mean closing every valve sold under the name automatically empties all connected piping. A manually operated drain or cap and an automatic underground drain are different arrangements.
The word “waste” here refers to draining water from the supply line. It does not make the valve a drain-waste-vent fitting or a sewer backwater valve.
Compare the actual drain arrangements
| Arrangement | What to verify | Do not assume |
|---|---|---|
| Handwheel valve with drain cock | Correct isolated side and drain operation | Automatic drainage simply from closing the handwheel |
| Valve with capped drain/vent | Exact cap, port and operating instructions | Any cap may be removed while pressurized |
| Underground drain design | Specified use, orientation, discharge and site conditions | An ordinary indoor valve can be buried in its place |
Choose the arrangement as part of the system design. A convenient valve location is not necessarily a location from which every low point can drain.
One checked drain/vent alternative: SharkBite 24635LF
Choose SharkBite 24635LF when its documented pipe connection and drain/vent arrangement suit the intended line. The current maker page (sharkbite.com) identifies a 3/4-inch × 3/4-inch push-to-connect stop valve with integrated drain/vent.
Skip it for an unconfirmed pipe standard, an automatic buried-drain replacement or an application the exact instructions do not cover. Do not describe it as a full-port ball valve merely because it is a push-to-connect shutoff.
On October 15, 2026, the standard new offer sold by Amazon.com showed stock with 24635LF in both the model and manufacturer-part fields. The separately listed 24634LF is the 1/2-inch version, not the selected 3/4-inch model.
Check SharkBite 24635LF stop valve with drain/vent on Amazon →
Match the pipe ends and the required service
Record the line’s size, material and actual connection standard. A threaded stop valve, solder-cup valve and push-to-connect valve are different connection choices.
The Watts stop-valve sheet (watts.com) separates threaded LFSWT from solder-end LFSWS. Similar letters in a product name can therefore change the required pipe connection.
For the featured SharkBite valve, confirm the exact supported pipe and specification. Do not assume that any plastic pipe with a familiar nominal size belongs in that connection.
Also verify temperature, pressure, fluid and location for the actual selected model. A general lead-free description does not establish every approval needed for the complete installation.
Draining depends on the whole pipe route
Water can remain where the line has low spots or where equipment prevents a clear drain path. Plan the entire route and each component instead of checking only the shutoff body.
Rain Bird’s drip-system winterization guidance (rainbird.com) highlights low spots and separate components such as filters, regulators and backflow protection. Those details require their own winterization checks.
A drain near the supply can help only with the portions that can actually drain to it under the specified procedure. It does not prove that a distant hose, valve or appliance is empty.
Use a complete system plan. Our plumbing winterization checklist covers the broader preparation beyond selecting this one valve.
Confirm orientation and a safe discharge path
Have the installer identify the upstream supply, the section to be isolated and the drain outlet. Apply any directional markings and the exact maker’s requirements.
Do not apply one model’s drain orientation to every valve that looks similar. Some arrangements have a separate drain control, and the correct sequence depends on the actual assembly.
Plan where discharged water will go and whether the outlet will remain accessible. Do not improvise a direct connection to a sewer or treat a drain outlet as backflow protection.
For below-grade work, confirm the exact valve’s suitability and the complete site design. Ordinary push-fitting burial guidance does not independently approve burying an operable stop valve or discharging through its port into soil.
A drain cap is a service component, not a spare plug
Identify the exact replacement cap, seal or repair kit if one is missing or damaged. Threading on a similar-looking cap does not establish that it is the specified replacement.
Do not remove a cap to investigate an unidentified live line. First establish the appropriate isolation and safe procedure for that exact system.
If a valve leaks, fails to isolate or will not drain as intended, have the complete assembly assessed. Additional tightening or replacing a visible cap may not address the underlying problem.
Keep model and repair-part information with the system record so future service starts with the correct valve rather than an approximate match.
Keep connection instructions separate from valve operation
The SharkBite push-system guide (sharkbite.com) covers connection preparation and full insertion. Those requirements are separate from selecting the valve orientation and safely operating its drain.
Use the exact current connection and valve instructions together. Do not copy a family-wide pressure, burial or installation statement as approval for every operating condition of the selected valve.
For outdoor faucet work, also check the faucet, connected hose and branch arrangement. Our outdoor faucet winterization guide addresses that related task.
Before normal use or seasonal shutdown, follow the specified checks for the complete installation. A valve with a drain is a useful component, not a guarantee against freezing.
Frequently asked questions
Does closing a stop-and-waste valve automatically drain every line?
No. Identify the exact drain design and the pipe route. Some arrangements require a separate drain operation, and low spots or connected components can retain water.
Is a stop-and-waste valve the same as a sewer backwater valve?
No. This guide concerns shutting off and draining a water-supply line, not preventing sewer backup.
Can a normal indoor stop valve be buried as an underground drain valve?
Do not assume so. Confirm the exact valve’s location approval, operating access, discharge arrangement and site requirements.
Is SharkBite 24635LF a full-port ball valve?
Do not treat it as one. The maker identifies it as a stop valve with drain/vent; select it by its exact specifications and intended operation.
Does a drain/vent valve guarantee freeze protection?
No. Winterization depends on the complete pipe route and every connected component, not the valve alone.
How we chose
This document-based guide makes no hands-on testing claim. We checked the current Watts LFSWT description and stop-valve sheet, the current SharkBite 24635LF page and linked push-system guide, and Rain Bird’s drip winterization guidance. On October 14, 2026, the linked standard new Amazon.com offer showed stock with matching model and manufacturer-part fields. It is a drain/vent stop-valve alternative, not an approved substitute for every underground stop-and-waste design. Read our selection method and about Plumbing Picks.
Primary sources
- Watts LFSWT (watts.com): downstream drain-cock function and threaded stop-and-waste configuration.
- Watts stop-valve sheet (watts.com): separate solder and threaded families; no complete installation procedure implied.
- SharkBite drain/vent stop-valve page (sharkbite.com): exact 24635LF 3/4-inch model and the separate 1/2-inch variant.
- SharkBite push-system guide (sharkbite.com): connection preparation/insertion, not valve-specific operating or burial approval.
- Rain Bird drip winterization guide (rainbird.com): low-point and component-specific drainage planning, not generic compressed-air instructions.