A shocking discovery in Woodinville
When a Woodinville homeowner called for a routine plumbing inspection, he had no idea a hidden leak had been wreaking havoc beneath his feet.
The signs had been whispering it for years—cracked tiles in the kitchen, a musty smell in the bathroom. The homeowner thought buckling tiles in his kitchen was normal wear and tear, but they were just symptoms of a deeper problem.
The long-term leak originated from the tub’s drain. White and black mold spread under the floor insulation.
Crawlspace insulation had absorbed a lot of water. Together with residual HVAC heat on the floor above, it was a breeding ground for black and white mold.
Crawling under the house, we uncovered the full story: The moisture had turned the crawl space into a miniature rainforest. Dripping pipes. Decayed insulation. Even an unexpected house guest—a “native” banana slug thriving quite nicely. All from a leaky walk-in shower. It had been silently feeding an ecosystem of mold.
Orange outline highlights a large banana slug enjoying the wet wood and mold.
Peeling back soaked insulation, we found the good stuff. Black and white mold had been spreading unnoticed for years. Wooden beams supporting the home were soft to the touch—springy!—a sign of long-term moisture exposure.
It was time to fix the leak for good.
Plumbing leaks may seem minor, but they can lead to bigger problems—mold.
In Snohomish County, moisture levels are naturally high. Mold growth can quickly get out of hand, putting your home and health at risk.
We love the Pacific Northwest, but living here comes with an obvious challenge for home health:
Rain.
Western Washington is home to some of the wettest areas on earth. From 35” inches of annual rain near the middle of Snohomish County, up to 110+” inches annually as you climb into the Cascade Mountains.
All that downfall wreaks havoc. Aging neighborhoods from the 1960s and 1970s have tired roofs and corroded plumbing. Small leaks and drips find their way into walls, floors and crawl spaces. With low ventilation and warm air, these houses become mold farms.
More people stay inside during wet months, too. And while some homeowners think mold is just an eyesore, the truth is far more concerning.
Left unchecked, mold spores circulate in the air, aggravating allergies, asthma, and respiratory issues. In extreme cases, mold exposure can lead to cognitive impairments and chronic illnesses.
Did you know?...
- According to the Washington State Department of Health,
- Asthma rates in Washington State are ranked among the highest in the nation.
- About 10% of households experience mold issues, with many cases linked to plumbing leaks.
- Studies also show that children exposed to household mold are 2.5 times more likely to develop asthma.
- Additionally, mold-related health claims make up a significant portion of homeowners’ insurance claims nationwide, often costing thousands in repairs and medical expenses.
It’s true
Unnoticed leaks under toilets, in crawl spaces, and around showers are famous for creating serious mold infestations.
The Woodinville home mentioned earlier was built in the early 1970s. He wasn’t the original owner, and it had been remodeled. Who knows when the leak started, and that makes it twice as bad.
- Constant moisture does long-term structure damage, and
- Insurance may deem it “neglect”.
The more likely it could have been fixed with routine maintenance, the more likely insurance is to deny those repairs are require the homeowner to pay out-of-pocket.
Why mold is more than a cosmetic issue
If you think mold is just an ugly black stain, think again.
- Airborne spores: Even if you can’t see mold, its spores circulate throughout your home, affecting air quality. Your HVAC filter won’t help if the source of the mold isn’t removed.
- Health impacts: Mold exposure can cause coughing, wheezing, headaches, brain fog, and worsened asthma—especially in children and older adults.
- Structural damage: Mold doesn’t just sit on the surface; it eats away at drywall, wood, and insulation, leading to costly repairs.
- Expensive repairs: Mold remediation and repair can cost a few thousand dollars to many tens of thousands. Homeowner insurance typically only covers mold damage if it’s caused by a sudden, covered event (like a busted water pipe). Mold damage caused by neglect or long-term issues is usually NOT covered.
How leaky plumbing fuels mold growth
In the Pacific Northwest, most homes have crawl spaces, which are naturally prone to moisture. When a plumbing leak goes unnoticed, it creates the perfect environment for mold to thrive. Some of the most common causes include:
- Leaky toilets: Moisture buildup under the flooring leads to warped tiles and hidden mold growth.
- Shower and tub leaks: Slow leaks from a walk-in shower can seep into the subfloor, causing damage for years before it’s detected.
- Leaky pipes in crawl spaces: The damp, enclosed environment under a home is the perfect breeding ground for mold, especially when combined with poor ventilation.
- Pinhole leaks in copper pipes: Water quality issues in areas like Lake Stevens can lead to pipe corrosion, which may start as a tiny drip but can become a full-blown mold problem over time.
Don’t be a slug farmer. You are more likely to get leaks fixed in a timely manner if you can see the clues.
Signs you might have a hidden leak and mold problem
Because mold often develops in unseen areas, homeowners might not recognize the warning signs until the damage is extensive. Here are key indicators to watch for:
- Buckling or sagging floors
- Discolored linoleum or cracking tiles
- Dark stains on drywall or ceiling
- A musty odor in your home, especially in bathrooms or basements
- Persistent allergy-like symptoms, such as sneezing, congestion, or itchy eyes
Misconceptions about mold: When to DIY fix, or get professional help
Many homeowners believe they can simply wipe mold away with bleach or run a fan to dry out damp areas. Unfortunately, these approaches don’t eliminate the problem—they make it worse!
- Bleach doesn’t kill mold. It only removes surface stains while leaving behind the root structure, allowing mold to return stronger than before.
- Fans can spread mold spores. Instead of solving the problem, fans distribute mold throughout your home.
- Heat accelerates mold growth. Some homeowners think they can dry out a mold problem, but warm, humid conditions can make it spread faster.
Simple ways to protect your home
Since plumbing issues are the leading cause of mold in Washington homes, a little bit of prevention can pay huge dividends. Start with a detailed inspection. Whether or not you use Stars and Stripes Plumbing, we recommend you do an annual whole-home plumbing inspection to catch leaks before they become disasters.
Smart inspections include the following (at a minimum):
- Check toilet seals and flanges for leaks
- Inspect shower and tub drains for slow leaks
- Examine crawl spaces for moisture buildup
- Test water pressure to prevent pipe wear and leaks
- Ensure shut-off valves are functioning properly—AND shows you where they are and how to use them in case of an emergency.
Inspections are only as good as the inspector and their experience recognizing problems.
If you get pro help, be sure you hire a licensed plumber who specializes in residential service. They have more advanced tools and years of experience recognizing and finding hidden problems. You get more value for your money.
“What if I see a mold issue?”
If you’ve noticed signs of mold or suspect a plumbing leak, don’t wait. A small drip today can lead to major mold growth in just a few months. Here’s what to do:
- Fix the leak issue: Call a plumber if you aren’t sure how to do it well yourself. Stopping the drips and moisture is the first step in keeping mold from growing and spreading. PLEASE NOTE: Plumbers can do a great job fixing leaks, but they do not clean up or repair mold issues. So…
- Schedule a mold inspection: If mold is already present, a professional remediation team can assess the severity and remove it properly. One company we can recommend in Snohomish County is PureDry.
- Invest in prevention: Regular plumbing maintenance and moisture control measures can save you thousands in repair costs.
Our van comes ready with advanced tools, technology and parts to fix a wide variety of leaks and prevent mold from starting.
Local expertise for Snohomish County homes
Stars and Stripes Plumbing specializes in leak detection and prevention for homes in Everett, Lynnwood, Lake Stevens, Woodinville, Marysville, Monroe and surrounding areas. Whether it’s a slow toilet leak or a corroding pipe, we help homeowners find issues so we can stop mold before it starts.
Schedule a plumbing inspection today
Book online | or call 425-244-6349
WANT TO LEARN MORE?
- Mold & air quality page on the Snohomish County Health Department website
- Statistics at the Washington State Department of Health website
- CDC website on mold
- Clean-air agency Indoor air quality overview and videos