Contact Pom Waterproofing. I know that there are excellent artists. In general, the company is large and has been operating for a long time. They did waterproofing of the basement for me last year, and I am satisfied with the quality of work and the decency of the specialists. Here you can read about the shut-off valve https://pomwaterproofing.ca/back-water-valve-installation/. What I liked is that they arrive quickly, or am I so lucky))