Must a New Brunswick irrigation system have backflow protection?

Yes — backflow protection is required on New Brunswick irrigation systems, and this is not optional. Any irrigation system connected to a potable (drinking) water supply must have an approved backflow prevention device installed, full stop.

Here's why this matters. An irrigation system creates what plumbers call a "cross-connection" — a point where your drinking water supply connects to a non-potable source. Without protection, a drop in municipal water pressure (from a water main break, firefighting demand, or pump failure) can cause contaminated water — fertilizers, pesticides, soil bacteria, even animal waste from your lawn — to be siphoned backward into the drinking water supply. This isn't a theoretical risk; it's the reason backflow prevention is standard practice across Canada.

The regulatory framework in New Brunswick falls under the National Plumbing Code of Canada, which NB has adopted, as well as local municipal water service bylaws. Most NB municipalities (Fredericton, Moncton, Saint John, and others) explicitly require backflow prevention on irrigation connections as a condition of water service. Some municipalities require the device to be inspected and tested annually by a certified backflow prevention tester. Your local municipality is the authoritative source on exactly what's required in your area — bylaws and inspection requirements do vary.

The right device depends on your system's risk level. For a standard residential lawn irrigation system, a Pressure Vacuum Breaker (PVB) or Reduced Pressure Zone (RPZ) assembly is typically specified. A PVB is the more common residential choice — it must be installed at least 30cm above the highest irrigation head. An RPZ offers higher protection and is sometimes required when fertilizer injectors (fertigation) are used, since that increases contamination risk significantly.

Practically speaking, if you're having an irrigation system installed, the contractor should be pulling the appropriate permit and including a compliant backflow preventer as part of the installation — this is not an add-on, it's a baseline requirement. If you're buying a home with an existing irrigation system, it's worth confirming the backflow device is present, properly installed, and up to date on any required testing.

This is firmly in professional territory. Backflow prevention installation involves your home's potable water supply, local plumbing code compliance, and in some municipalities, mandatory third-party testing. A qualified irrigation contractor in NB will know the local requirements and install the correct device. If you need help finding one, New Brunswick Landscaping can match you with a local irrigation professional at no cost — find contractors through the New Brunswick Construction Network at newbrunswickconstructionnetwork.com.