The case of the leaking back flow prevention valve.
A back flow prevention valve is required in some jurisdictions. It simply prevents water from a boiler or hydronic heating system from getting into and contaminating drinking water for the house. The circulating hot water should be contained within the system and kept separated.
This is a circulating, hot water boiler system.
When I run into these in older homes and the boiler is very old I often do not see a back flow prevention valve.
The boiler in this house had been replaced in previous years, and was not very old. When the old boiler was replaced a new back flow prevention valve was installed.
However, for whatever reason, this one was leaking.
This pin-hole leak had caused rust and oxidation, as water and air are wont to do, and dripping water could be seen on my finger after rubbing under the rust.
My recommendation: during inspections we see what we see. Some things need immediate attention. A plumbing leak is one of those things as leaks can often get very bad very quickly. This is a simple fix for a professional plumber, and the valves are not very expensive.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560