A Seller Property Information Sheet is a form designed to give buyers additional information about the house. It asks sellers to list any known defects, pending work orders or tax increases, oversight by any regulatory body such as conservation authorities, etc. The idea is that, if you disclose everything up front, you reduce your liability. Here’s the problem: it doesn’t reduce liability, primarily because they are often filled out wrong.
If you don’t say anything about the sprinkler system, believing it to be fine, the buyers have the responsibility of making sure that they do an inspection before closing. If it fails after closing, you are better protected as long as you didn’t hide any defects.
If, however, you say on the SPIS that there are no issues with the sprinkler system, and it turns out that there are, you have now been untruthful. This will cause a much bigger problem down the line, even if you honestly believed that there were no problems.
My view on the SPIS form is that I love them when I’m acting for buyers and hate them when I’m acting for sellers. If you are selling, you are probably better off not signing the form unless you are absolutely positive that your answers are correct.