Guaranteed Plumbing
Company Overview
At Guaranteed Plumbing, along with our partner East Bay Gas Lines, we ensure top-notch quality and customer satisfaction for all our customers. Our company is a full-service plumbing and gas line provider, licensed, bonded, and insured, with a deep understanding of city codes. Additionally, we are a trusted vendor for the Town of Danville Building Department.
Our service area includes Danville, Alamo, Contra Costa, Alameda Counties, and the greater East Bay region. Guaranteed Plumbing and East Bay Gas Lines collaborate with homeowners, general contractors, restaurants, businesses, retailers, property managers, real estate agents, and government entities. Whether your project is simple or intricate, standard or tailored, we are equipped to manage any plumbing or gas line task.
Marcus Madrid founded Guaranteed Plumbing, Inc. in Danville, California in 2003, with an emphasis on residential service and renovation work. Thanks to ""word of mouth"" referrals that highlight the exceptional skill and efficiency of our team, we quickly grew to handle a wide range of residential and commercial projects across the East Bay.
Marcus Madrid values having a capable, reliable, and friendly team, and he participates in every project himself. He is present from the planning stage through to the project's completion. We appreciate the significance of fostering long-term customer connections, working with clients to provide economical and inventive plumbing options. Our team pays meticulous attention to detail in every project, whether designing a large commercial installation or replacing a kitchen faucet.
Marcus Madrid is a second-generation plumber, having started learning the trade alongside his father at the age of 12. He has lived in the Bay Area for more than 30 years and holds a Bachelor's Degree from Cal Poly San Luis Obispo.
Business Services
- Bathtub installation
- Bathtub repair
- Drain installation
- Drain repair
- Faucet installation
- Faucet repair
- Garbage disposal repair
- Gas line installation
- Gas line repair
- Hot water recirculation pump installation
- Hot water recirculation pump repair
- Plumbing inspection
- Plumbing installation or replacement
- Plumbing repair
- Sewer installation
- Sewer repair
- Shower installation
- Shower repair
- Sink installation
- Sink repair
- Toilet installation
- Toilet repair
- Water heater installation
- Water heater repair
- Water pipe installation
- Water pipe repair
Business Location & Hours
Mon: | 7:00 AM - 5:00 PM |
Tue: | 7:00 AM - 5:00 PM |
Wed: | 7:00 AM - 5:00 PM |
Thu: | 7:00 AM - 5:00 PM |
Fri: | 7:00 AM - 5:00 PM |
Sat: | Closed |
Sun: | Closed |
Recommended Customer Reviews

Marcus and his team are comprehensive and professional. They really listen to what the problem is and look at every detail to sold issues. Also, the follow up was complete.

Great Experience!!! I had a hot water heater issue and was in a panic. Called and Gary came out same day to provide a quote. He ended up replacing everything the same day with excellent pricing. He was very professional and knowledgeable. Would highly recommend!

Frustrating experience with this company. I submitted an online request for a quote on Sunday. By Wednesday afternoon, I hadn't heard anything back so I gave them a call. They were polite on the phone and scheduled an appointment for a week out to give me an estimate on my project. About ten minutes before they were to arrive at my home, I got a call that they could no longer make the appointment. This was frustrating as I had made arrangements to be available for the appointment, which was then cancelled with extremely short notice. To make matters worse, they have told me they cannot give me an estimate at all and are not able to take on my project due to my location and a lack of manpower. Both circumstances were known ahead of time yet I got the call minutes before they were to arrive. I understand things happen but after pursuing them multiple times to give them my business, they still ended up letting me down. Who knows how far out my project is now as I have to search for a new company.

Johnny Utz was great. Guaranteed came and took care of our water heater all around great service. Been using them for many years and will continue to

Johnny was our plumber, arrived on time, did an excellent job on all 3 repairs, wore a mask, had a great sense of humor and even laughed at my husband's jokes! Now I feel totally safe from drips and rocky toilets!

Johnny Utz came right on time this morning. He was extremely knowledgeable and fixed everything quickly. He also did some other work outside of plumbing since wr had his time for an hour. I highly recommend guaranteed plumbing and Johnny Utz was great! I will use them again.

We love Guaranteed Plumbing! John came out today and fixed our leaky shower head AND our gas fireplace. He was very professional, wore a mask and courteous and kind. I felt completely safe having in our house (during Covid). He was a pleasure to speak with and he's a dog person which made things even better. Highly recommend GP and John!

We used Guaranteed Plumbing to service/repair our HTP water heater.
Their first time out was spent troubleshooting the issue. The tech was friendly and followed Covid protocol. He listened to our issues and we told him what we had already tried on our own and history with HTP as well. During the first visit he spent almost the full time on the phone with HTP. At the end of the two hours he gave us a website and said we could order parts (he gave us part numbers and did explain going thru this website would be cost effective so we appreciated that). Once the parts arrived we were to call back for install of parts. He also said our gas line was undersized and so we called PG&E that day to come out.
First appointment was $430 dollars (for troubleshooting) and our system was still not working.
We had PG&E out the same day because they don't mess around when it comes to gas line issues. Interestingly PG&E said unfortunately undersized gas lines are blamed often. PG&E tested lines and pressure against recommended pressure output on the system and gave the all clear.
Parts arrived and we called to schedule 2nd appointment. The same tech came out for round 2. He installed the new parts and initially the unit fired up but then glitched again. He was on the phone with HTP again (who frankly wasn't much help) and again there was mention that it still wasn't working due to the gas line.
Since he was suggesting the gas line be replaced we asked for a quote for the gas line and also asked for a quote for a new system (if needed). He wrote all of this on our receipt and said we would get us an email with those quotes but that never happened.
At the end of the 2nd appointment he seemed flustered and quite frankly we were too. After another $430 charge we still don't have our water heater up and running not to mention the cost of the parts we had to order.
My husband called the owner and left a voicemail and no return call.
After the no quote, no return phone call we decided at that point we would not have them return. By this point we have spent over $1,000 for the two appointments, and parts, and the system still isn't working.
We contacted another company who came out at NO CHARGE. They did say we needed a different part all together and they explained they will charge once we get the part, they Install, and fix the issue. This new company also confirmed the gas line is NOT undersized for the unit and pressure is fine.
While Guaranteed Plumbing tried (and did Install two new parts on the 2nd visit) we don't have confidence he knew exactly what he was doing with this particular system.
Disappointed that in all we were charged $860.00 by Guaranteed with no fix, and no follow up.

Had some plumbing problems with an older toilet which were beyond my good intentions and lame skills. Guaranteed Plumbing responded quickly. Our plumber, Gary Sanchez, was very pleasant, courteous and efficient. He wore a mask and was careful to maintain social distancing protocols. Beyond the repairs, he made some suggestions without any kind of a ""hard sell"". We wouldn't hesitate to use Gary and Guaranteed Plumbing in the future.

We had a great experience with Johnny today. He diagnosed our problem immediately and fixed it quickly. Very friendly and knowledgeable!! Thanks so much!!