What a Cross Connection Is
The regulations call the risk a cross connection, meaning any point where the potable supply meets something that is not potable. Massachusetts drinking water regulations are blunt about it: no physical cross connection may be maintained between a public water system and any plumbing, fixture or device by which nonpotable water or other substances might flow into the potable system, unless it is protected by an approved backflow prevention device.
The same regulations require devices to be installed, according to the degree of hazard involved, at all fixtures and equipment where backflow or back siphonage may occur.
In practice the places this comes up in an ordinary building are narrower and more familiar than that language suggests.
Where They Actually Turn Up
Irrigation systems. The most common residential case by a distance. A lawn system sits in contact with soil, fertilizer and whatever else is on the ground, and it connects to the house supply. That connection needs protecting, which is why irrigation work and backflow work arrive together.
Boiler fill lines. A heating system’s water is not drinking water: it has sat in cast iron for years and may carry treatment chemicals. The fill line is a direct connection between that loop and the potable supply, so it gets a device. The heating page covers the rest of the boiler side.
Commercial equipment. Anything that connects the water supply to a process, a tank, a chemical or a piece of machinery. This is the bulk of it on the commercial side, and the commercial page covers how we work on occupied buildings.
Hose connections in certain settings, and outdoor supplies where something could be drawn back.
What the Work Involves
Choosing the device is the part that has to be right, because the correct type depends on how serious the hazard is rather than on what is convenient. Getting that wrong means either a device that does not protect enough or one that is unnecessary for the situation.
Then there is where it goes. These devices need to be accessible, because they have to be inspected and serviced periodically, and one fitted somewhere awkward creates a problem every year thereafter. Several types discharge water when they operate, so they need somewhere for that to go, which is a design question rather than something to work out afterward.
Freezing matters here more than in many places. A device on an outdoor irrigation connection that is not properly drained down does not survive a Massachusetts January, and the failure shows up as a flooded spring rather than a cold winter.
Testing Is a Separate Thing, and Worth Knowing About
Massachusetts requires these devices to be tested on a schedule, and the regulations are specific: all backflow prevention device tests must be conducted by a certified Backflow Prevention Device Tester. Reduced pressure backflow preventers are inspected semiannually, and double check valve assemblies are tested annually.
That certification is issued by the state and is separate from a plumbing license. It is worth knowing as a building owner, because the testing schedule is a real obligation with a real record behind it, and it is the sort of thing that surfaces at the worst moment if nobody has been keeping track.
If your device has failed a test, or is due for replacement, that is installation work and it is ours.
Permits and Licensed Work
Massachusetts requires a permit before plumbing work is installed, altered, replaced or repaired, with limited exceptions, and only a licensed master or journeyman may apply for one. Our license numbers are published on the licenses page against the Commonwealth’s own register.
Commercial Buildings and Rentals
On a commercial property or a building with tenants, backflow is usually one line in a longer list of things that have to be kept current, and it tends to be the line that gets forgotten until an inspection asks about it.
What makes it manageable is knowing what devices the building actually has, where they are, and what condition they are in. That is frequently the first real piece of work on an older property, because the record and the reality have drifted apart. The property managers page covers how we work with buildings that have tenants in them.
Where We Work
Casper works out of Quincy and the crew covers the South Shore and into Boston. The Quincy page and the Weymouth page describe each town, and the service area page lists the rest.
Call (617) 549-5734 or use the contact page. Telling us what the device serves, and whether it has failed a test or is being installed new, gets you a more useful answer on the first call.
Questions We Hear
Why Does My Sprinkler System Need One?
Because an irrigation system sits in contact with soil and whatever is on it, and it connects directly to the water supply for the house. If pressure in the main drops, even briefly, the direction of flow can reverse. The device is what stops that reaching the drinking water, which is why irrigation connections are one of the most common places you find one.
What Happens If the Pressure in the Main Drops?
For a short period water can move the wrong way, which is called back siphonage. It happens after a main break, when a hydrant is opened, or when there is a heavy draw nearby. On its own it is brief and harmless; the risk is entirely about what is connected at the other end and whether anything can be pulled back.
Does My Boiler Fill Line Need Protection?
Generally yes. Water that has been sitting in a heating loop is not drinking water, and it may carry treatment chemicals, so the fill line is a connection between two very different kinds of water. That is exactly the situation these devices exist for, and it is standard on a heating system.
My Device Failed Its Test. What Now?
A device that has failed either needs repair or replacement, and which of those depends on the type, its age and what has gone wrong. That part is plumbing work. Bring us what the test found and we will tell you what the device needs rather than defaulting to replacing it.
Why Did Mine Break Over the Winter?
Most often because an outdoor device was not fully drained down before the freeze. Water left inside expands, and the damage usually shows up in spring when the system is turned back on rather than in January when it happened. It is one of the more preventable failures, and it is worth including in how the system is shut down each year.
Can You Look at a Commercial Building’s Devices?
Yes. On a commercial property it is common to find the paperwork and the building disagreeing about what is installed and where, so establishing what is actually there is often the first useful job. Call (617) 549-5734 or use the contact page and we can work through it.