A sink vacuum breaker is a plumbing safety device designed to prevent contaminated water from flowing backward into your clean water supply.
Based on standard plumbing definitions and the provided reference, a vacuum breaker is a backflow preventer. It is a threaded device that typically attaches onto a faucet, including those used at sinks. Its primary function is crucial: it prevents water from flowing backwards into the plumbing system.
This backward flow, known as "backflow," can occur due to changes in water pressure, such as when there is a sudden drop in the supply pressure (like during a water main break) or an increase in pressure on the customer's side (like from a pump or thermal expansion). If a hose is submerged in potentially contaminated water (e.g., a bucket of cleaning solution, a fish tank, or even just standing water in a sink basin), backflow could draw that contaminated water into the potable water pipes, potentially affecting your drinking water and that of your neighbors.
Understanding Backflow Prevention
Backflow is a serious health risk. It can introduce harmful substances like chemicals, fertilizers, and waste into the public water system. Devices like vacuum breakers act as barriers to stop this from happening.
How They Work
A vacuum breaker typically contains a valve, often a float or disc, that remains open when water is flowing forward normally. However, if the water pressure drops or a vacuum is created in the supply line, the valve closes or a vent opens, breaking the potential siphon effect and preventing water from being drawn back from the faucet outlet into the main plumbing.
Why They Are Important
- Protects Water Quality: They safeguard your household's and the community's drinking water from contamination.
- Code Compliance: Many plumbing codes require the installation of vacuum breakers on faucets, especially those with hose connections or where there's a risk of the outlet being submerged.
- Simple and Effective: They are relatively simple, inexpensive devices that provide essential protection.
Where Are They Used?
While the question specifically asks about sinks, vacuum breakers are commonly found on:
- Outdoor hose bibs (sillcocks)
- Utility sink faucets
- Hair salon sinks
- Boiler feed lines
- Irrigation systems
For a sink faucet, especially one that might be used with a hose attachment or where the possibility of submerging the spout exists (like in a utility or salon sink), a vacuum breaker is a key component for maintaining water safety.
