This canvas cover is waterproof the way a vinyl jacket is (which is to say it will keep rain out for about 30 minutes before becoming completely soaked). Even when keeping my firepit in the garage over the winter, the spring and fall rains were enough to keep it consistenly wet enough to provide a breeding ground for mold and slime. The greenish brown hue was not only unappealing but caused the cover to disintegrate over time.

This cover only lasted one full year (bought Oct 2017 and threw away Oct 2018) before it tore apart like tissue paper when i tried to take it off my firepit. The 1 foot rip happened right where my hand grabbed and pulled. Basically the materials just completely succumbed to 3 season of elements and the lightest pressure caused it to tear. 

It was a nice fit while it lasted but having a cover that cant handle a moderate (midwest US) outdoor environment isnt very useful. Ill be upgrading to a simple tarp next year.