How to Find the Best Plumbers in Ontario, CA

Start with our Top 10 rankings for Ontario — each provider is ranked by real Google rating, review volume, and response time, not paid placement.

17 listed providers serve Ontario with an average 4.9-star Google rating. Prioritize providers with at least a 4.5-star rating and 10 or more reviews. Volume matters here: a 5.0 from four reviews is much less trustworthy than a 4.7 from two hundred.

Ask about credentials relevant to plumbers: licensing, general liability insurance, worker's comp on crew, and any industry-specific certifications required or recommended in California. Most state licensing boards have a public lookup tool you can use to confirm a license is active.

Once you have a shortlist of 3-5 candidates, request written quotes and compare scope of work side-by-side — not just the bottom-line price. The lowest quote often wins on price by quietly cutting materials, crew experience, or cleanup. An itemized comparison surfaces those gaps before you sign.

Pay attention to response speed. A good plumber usually responds within 24 hours on weekdays. Slow responses before you're a customer predict slower responses once the job is underway.

Check references specific to Ontario or nearby neighborhoods when possible. A provider with glowing reviews two hours away but none near you may have expanded coverage faster than crew quality.

Currently highly-rated in Ontario: Dependable Rooter & Plumbing, Royalty Plumbing and Drain and Redhead Rooter Plumbing Drain Cleaning & Hydrojetting. Rankings update hourly as new reviews come in, so the exact order on the Top 10 page may differ.