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Emergency plumber at your door in 60 to 90 minutes across the San Fernando Valley, Santa Clarita & LA CountyEmergency response in the Valley & LA County

Slab, wall & underground leaks

Leak detection that finds it before you open a wall.

Hidden leaks quietly raise water bills, damage floors and weaken foundations. Professional locating equipment pinpoints where the water is escaping, under the slab, inside a wall or in the yard, so the repair opening is as small as possible.

Leak detection

Signs of a hidden leak.

Many leaks never show up as a puddle. These are the clues that usually point to one.

  • Water bill jumpedUsage went up with no change in habits.
  • Meter moves with everything offThe clearest sign water is escaping somewhere.
  • Sound of running waterHissing or running water with all fixtures closed.
  • Warm spots on the floorA hot water line leaking under a slab.
  • Damp drywall or baseboardsStains, bubbling paint or musty odors.
  • Soggy yard areasA leaking service line between the meter and the house.

How it works

How we locate hidden leaks.

We start by confirming there is a leak and isolating it: is it on the hot or cold side, inside the house or on the service line from the meter? Pressure testing narrows the search to the affected line.

Then locating equipment pinpoints the leak itself. Depending on the situation that can mean acoustic listening to hear water escaping under concrete, pipe locating to trace the line's path, or moisture readings to map where water is spreading in walls and floors.

Once we know where it is, we explain the repair options: a spot repair through a small opening, rerouting the line, or repiping a failing section. Slab leaks in older Valley homes, for example, are often better solved with a reroute than by breaking the floor.

  • Isolate. Hot or cold, inside or service line.
  • Pinpoint. Acoustic, locating and moisture tools.
  • Repair smart. Spot repair, reroute or repipe.
New Flow Plumbing technician using pipe locating equipment beside a branded service van

Our process

From suspicion to a dry house.

Clear steps, explained before anything happens, so you always know what comes next.

  1. Confirm the leak

    Meter checks and pressure testing confirm and isolate the leaking line.

  2. Pinpoint the location

    Locating equipment finds the leak with minimal disruption.

  3. Recommend the repair

    Spot repair, reroute or repipe, explained with pros and cons.

  4. Repair and retest

    The fix is made and the system is pressure tested again.

Good to know

Where leaks usually hide.

These are the leak locations we find most often in Los Angeles homes and buildings.

  • 01

    Under the slab

    Copper lines under concrete foundations, common in post-war Valley homes.

  • 02

    Inside walls

    Supply lines and fittings behind showers, sinks and appliances.

  • 03

    Service line

    The water line between the meter and the house, often galvanized or aging copper.

  • 04

    Fixtures and valves

    Toilets that run silently, dripping valves and failing supply hoses.

FAQ

Leak detection questions.

Straight answers to what homeowners ask us most. Call if yours is not here.

Call 818-538-4958

Common signs include warm spots on the floor, the sound of running water, cracks in flooring, and a water meter that moves when everything is off.

Not always. After pinpointing the leak, rerouting the line through walls or the attic can avoid breaking the slab. We will explain both options.

Yes. A running toilet or a small underground leak can waste a large amount of water without any visible sign.

It depends on your policy. Damage from sudden leaks is often treated differently from gradual leaks. Check with your insurer; our documentation can support a claim.

Customer reviews

Customers on leak detection.

Read all reviews

Reviews come straight from our Google Business Profile.

Posted on Google Google
Theodore Nilsson profile picture
Theodore Nilsson
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New Flow came out to my mothers house in Reseda and was able to clear the main line blockage. They were there within an hour and had very reasonable pricing. While there they identified another problem with the pipping(it is a 100 year old house lol) and came up with an option to replace some of the pipping. Definitely will be using them again for any problems down in the valley.
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Valerie profile picture
Valerie
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Whenever something goes wrong at our North Hollywood condo property, Art answers the phone day or night, which is why New Flow Plumbing has handled our plumbing since the place was built. Just last week a huge problem hit at 10:00 pm with all the tenants stressing out, but they had someone walking through the door in twenty minutes to get it taken care of. They show up ready to work seven days a week for the small stuff and the emergencies alike, so I always know we are covered.
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Michael profile picture
Michael
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Had a sewage back up at a unit and Art was able to take care of my problem. Due to it being an older house it had quite significant problems (old piping, no clear out,etc). He took care of the clog, add clear out, and also discovered the toilets that were installed were incorrect ones since forever and replaced both toilets as well. He also gave me advice on what he would do with the current drainage problem and what he would do temporarily, and or the future for my piping. Was very reasonably priced. 100% satisfied with the service he provided.
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Cherrie ! profile picture
Cherrie !
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Shower was way too cold. Looked at the tank and could tell it was completely done, so we reached out to New flow to fix the plumbing in Granada Hills. The tech got the new hot water heater put in and even cleaned up some sloppy copper fittings left behind from our previous remodel so everything lined up straight. He was wrapped up and out the door by 3p, and the hot water was running before he left.
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Ava-Lynnette De La Torre profile picture
Ava-Lynnette De La Torre
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
Water was backing up into both my toilet and bathtub from a main line clog. A few plumbers gave weird replies, including one guy who threw out a random quote without even checking the pipes. I usually handle small things myself, but I needed real help here. Art came in and mapped out the whole line, running a camera to show me the blockages on the screen. He pushed past 60 feet clearing tree roots and debris, explaining the fix as he went. The final bill matched his quote. Thanks to them I can finally take a shower.
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Melanie Hernandez profile picture
Melanie Hernandez
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Great work from the best plumbers in the valley. I had a pretty big job done. They replaced the main water pipe out to the street. It was completed on time and they kept me informed during the down time (waiting for the city to approve the permit.) I would use them again. They are pleasant to work with.
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Taye325 profile picture
Taye325
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If you need a reliable plumber in Valley Village, save their number right now. Our new tenants moved into our rental last weekend and immediately hit us with a no hot water text. Found New Flow on Google, liked what I saw on their page, and gave them a call. Arman sent someone out just a few hours later. We looked at the old twenty year unit and agreed a full replacement made the most sense. They knocked it out the exact same day, saved my weekend, and kept the tenants happy. Already passed his name to a buddy of mine who hired him shortly after.
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Ava Lamison profile picture
Ava Lamison
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My parent's toilet was leaking and after messaging different places, I told my parents this place could fix our problem. Arman was the one who helped us out and after talking to him about a possible broken wax ring, he found the actual problem, roots in our pipes. He hydrojetted the roots and installed something to help keep the roots from growing for the next few years. So if you're have problems related to pipes, my family and I highly recommend coming here.
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tal abutbul profile picture
tal abutbul
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We have been calling New Flow for plumbing services ever since they warned us six years ago that our ancient drain pipes were on their last legs. When the system finally failed, we shopped around for bids on a full repipe. Every single plumber gave us quotes without stepping foot under the house, except them. The team crawled under there, filmed the pipes, and showed us that our water lines were still completely fine. Arman gave us a fair quote for just the drains, and his crew finished the work in one day. Hard to find contractors this upfront and genuine.
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Chloe profile picture
Chloe
Google star 1Google star 2Google star 3Google star 4Google star 5Trustindex verifies that the original source of the review is Google.
I cannot compliment New Flow Plumbing enough. They were recommended by our selling real estate agent for a sewage line inspection. They came out quickly, and Arman was very professional and polite right away. He was able to service the sewage line, provide thorough, expert knowledge, and give us recommendations. The pricing is excellent and fair, and I would definitely recommend using their services again. The HD video was provided for our own viewing, and it was emailed to us within hours of the visit. Overall a very enjoyable experience. 5 stars does not do it justice. Thanks again!!

Water bill suddenly higher?

Call 818-538-4958 and we will help you find out where the water is going.