The answer to 'average cost of backflow preventer' is that the typical range for a backflow preventer installation can vary widely, from around $150 to $1,000 or more. The actual cost depends on several factors, including the type of backflow preventer, the complexity of the installation, the location and accessibility of the plumbing, and the labor rates in your local area.
Backflow preventers are an essential plumbing component that help protect your home's water supply from contamination. They are required by most local building codes, so it's important to have a professional plumber assess your specific needs and provide an accurate quote for the installation.