When remodeling a bathroom or trying to repair a dripping faucet, you’ll soon find yourself surrounded by a web of plumbing terms. One source of confusion for homeowners and do-it-yourselfers is the acronym REV as it relates to a shut off valve called the turn stop. What is it, really, and what does it mean for the water in your house?
Whether you’re working with a kitchen sink or a toilet, you should know this stuff if you love your plumbing – or just want to avoid flooding your home and needing crawl space repair. Below, we will demystify these complex phrases and answer the most asked questions regarding shut-off valves.
Decoding "REV" in Plumbing Contexts
When looking at fixtures or reading product specifications for a 1/4 turn stop valve, the term REV typically stands for one of two things:
- Revolution: In the context of a 1/4 turn valve, it most commonly refers to a "Revolution." Unlike older multi-turn valves that require several full rotations to close, a modern valve only requires a quarter of a revolution (90 degrees) to fully open or close the water flow.
- Reverse: In the context of commercial plumbing, it may refer to a "Reverse Angle" stop, in which the inlet and outlet ports are engineered for unique piping arrangements that conventional angle stops can't accommodate. (Also, it is not uncommon to see it just meaning "Revision" in a manufacturer's technical spec sheet, like "Rev A" or "Rev B").
What is the Purpose of a Stop Valve?
A turn stop valve (also known as a shut-off valve, angle stop, or straight stop) is an isolation valve installed on the water supply lines connecting your home's main pipes to individual fixtures like toilets, faucets, washing machines, and refrigerators.
It’s designed so that you can turn off the water supply to one fixture without shutting off water to the whole house. This allows services, repairs or stop leaks in emergencies in incredibly short times and highly localized.
How Does a Turn Valve Work?
There are two main types of shut-off valves, but the 1/4 turn variation is the modern standard for residential construction due to its reliability.
How it works: Inside the brass or plastic body of the 1/4 turn valve sits a small sphere with a hole drilled directly through its center. This is known as a ball valve mechanism.
- When Open: The hole in the ball aligns directly with the pipe, allowing water to flow freely to your fixture.
- When Closed: By giving the handle a 1/4 REV (revolution), the ball rotates exactly 90 degrees. The solid, smooth side of the ball now blocks the pipe, instantly and securely stopping the water pressure.
Which Way Do You Turn a Stop Valve?
During a sudden water leak, you may be too distracted in a panic to remember which direction to turn the handle.The universal rule for nearly all standard plumbing valves is the same:
- To Close (Shut Off Water): Turn handle to right "righty-tighty". A 1/4 turn valve handle will usually be at a right angle (forming a cross) to the water pipe when it is completely shut.
- To Open (Turn On Water): Turn the handle to the left ("lefty-loosey"). When the valve is open completely, the handle will be parallel (in line) to the pipe.
Other Common Names for a Turn Stop Valve
When shopping at a hardware store, you might not see the exact phrasing on the packaging. Here are other names professionals use interchangeably:
- Angle Stop: Used when the water pipe comes directly out of the wall, creating a 90-degree angle to the supply line.
- Straight Stop: Used when the water pipe comes straight up through the floor.
- Quarter-Turn Shut-Off: Highlighting the specific 1/4 revolution ball-valve mechanism.
How to Stop a Turn Valve from Leaking?
A leaking valve under your sink can cause significant cabinet and drywall damage over time. If your valve is dripping, follow these steps:
- Tighten the Packing Nut: If the water is leaking from just behind the handle, you will need to tighten the packing nut (the nut located just behind the handle) gently with an adjustable wrench. Avoid over-tightening, as you might crack the brass.
- Replace the Valve: Contemporary 1/4 turn ball valves have Teflon or rubber seats in the ball assembly itself. In contrast to the older style multi-turn compression valves that use a replaceable washer, the parts within a 1/4 turn valve typically cannot be rebuilt with any degree of ease. If tightening the nut doesn't stop the leak, your best bet is to shut off the home's main water supply and replace the entire valve assembly.
Knowing the terms and How to of your Dive Home Shutdown Valves will allow you to take care of small leaks and fixture upgrades without feeling that you need to call in a plumber for advice or help. Is "REV" the quarter turn of the internal ball, a reverse angle configuration or a spec sheet revision?
With a little knowledge of which way to turn the handle, how the inner mechanism shuts off the water, and when a full replacement is necessary rather than a simple repair, you can save your home from water damage and keep your plumbing connections tight for years to come.
