Nor-Cal Maintenance Is Diamond Certified
Rated Highest in Quality and Helpful Expertise by American Ratings Corporation, from phone surveys of verified customers.
The rating
What does Diamond Certified mean?
It’s a rating from American Ratings Corporation, a research company in Petaluma. Instead of collecting online reviews, it surveys a company’s verified customers by phone and checks its license, insurance and complaint record. Companies that score high enough on quality and helpful expertise and pass the credential checks earn the award.
Our results
How did Nor-Cal Maintenance score?
Nor-Cal Maintenance has been Diamond Certified since December 2023 and rated Highest in Quality and Helpful Expertise for three consecutive years. Its report shows 52 verified customer survey responses with a 4.8 average star score, and its license, liability insurance and workers’ compensation were confirmed in the credential checks.
“They’re very thorough and they call ahead of time to let you know that they’re coming. I’m happy with their service.”
“They have good customer service and you definitely get what you pay for.”
Video profile
Watch Dave's Diamond Certified video
If something goes wrong
What is the Diamond Certified Performance Guarantee?
It’s a backstop run by American Ratings Corporation, not by us. If you hire a Diamond Certified company, aren’t satisfied and can’t resolve it with the company, you can contact Diamond Certified, which will try to mediate. Its own terms page explains the limits and deadlines, so read the details there.
Diamond Certified also publishes short expert videos from the companies it rates. Dave recorded two: one on choosing gutter covers, where he explains why the debris from your trees and the pitch of your roof decide which cover works, and one on hiring a pressure washing company.
FAQ
About the Rating
Is Diamond Certified the same as Google reviews?
No. Anyone with a Google account can post a review. Diamond Certified surveys are phone calls to a company’s verified customers, run by American Ratings Corporation. Nor-Cal Maintenance has both: the survey results on its Diamond Certified report and public reviews on its two Google profiles.
Where can I read the survey responses?
On Nor-Cal Maintenance’s Diamond Certified company report at dccert.org/2754. It lists the 52 survey responses in the customers’ own words, along with the credential checks and Dave’s two expert videos.
Does the rating get checked again?
Yes. The report shows the company rated Highest in Quality and Helpful Expertise three years in a row since it was first certified in December 2023, and the summary at the top of the report was last updated in December 2025.
Who runs Diamond Certified?
American Ratings Corporation, based on Southpoint Boulevard in Petaluma. It rates local companies across the San Francisco Bay Area and publishes a report for each one it certifies, with the surveys, credential checks and articles about the company.
Talk to Dave's team
See why customers rate us this way
Call (707) 940-7875 for a free estimate on your gutters or roof.