Surfactant leaching is an alarming but harmless occurrence that is bound to happen around your home at one point or another. If you have painted walls or siding, there's a chance you will see or have seen surfactant leaching around your home. In this guide, we'll explain what surfactant leaching is, how it happens and ultimately, how you can fix and prevent it in the future.

Surfactant leaching occurs when the concentration of water-soluble paint ingredients called "surfactants" surface after using latex paint. Surfactant leaching is a brown, sticky substance on painted walls. It can also look like tan, brown or clear spots or paint streaks. It can also feel glossy, soapy, oily or sticky. While you may know what surfactant leaching is supposed to look like, it can be hard to distinguish it from other common household problems.

Luckily, the difference between surfactant leaching and mold is quite distinct. Mold is typically fuzzy or slimy and has a musty odor. Up close, you'll likely see the circular mold spores. Normally, surfactant leaching collects to look like water droplets and won't have an odor. In addition, mold signals a deeper issue, while surfactant leaching is a surface issue related to a breakdown in the paint chemistry.

Unless you've bought an older home, you can quickly rule out nicotine stains if you aren't a smoker. Surfactant leaching and nicotine damage are similar in color, but nicotine damage will smell like cigarettes, while surfactant leaching doesn't have a smell. Nicotine damage also won't feel oily or sticky like surfactant leaching. Lastly, nicotine damage tends to leave a yellow-brown film rather than droplets. In the most severe cases of nicotine damage, you can see outlines of hung pictures and lamps protecting a wall section from discoloration.

While unsightly, surfactant leaching isn't harmful to humans. While the term "surfactant" may seem like something to worry about, surfactants are in many everyday household items. Laundry detergent, for example, uses surfactants to lift stains.

Surfactant leaching poses no danger to you and signals no issues with your home. It is purely cosmetic and can go away on its own depending on proper drying methods in your home. If you've found surfactant leaching on exterior paint, the elements will quickly remove the appearance of leaching over time without your help.

There are two leading causes of surfactant leaching. However, latex paints contain surfactants designed to make applying them possible, meaning any latex paint could leach surfactants over time. Moisture and cooler temperatures can increase the chances of finding surfactant leaching.

• Moisture – Moisture is the number one cause of surfactant leaching since it interferes with curing. Moisture extracts and concentrates different water-soluble materials from within the paint onto the surface. When the water evaporates, a concentrated residue is left behind, causing staining, unsightly runs, and gloss patterns. Bathrooms, laundry rooms and kitchens are the interior spaces most susceptible to surfactant leaching.
• Cooler Temperatures – Cooler temperatures can lead to surfactant leaching because they slow the paint's curing process, allowing surfactants to separate and float to the top of the coating.
• BONUS: Paint Color – Dark paint colors don't cause surfactant leaching but are more susceptible because they contain additional surfactants.

Determining how to fix surfactant leaching depends on the location of the surface where it occurred. Regardless of where surfactant leaching has occurred, it's important to avoid painting over the stains. Doing this traps the oily residue and will cause it to worsen over time. The fresh paint also won't adhere properly, which will cause bubbling and blistering.

If surfactant leaching occurs indoors, wash the affected area with soap and water and rinse. Discoloration may occur several times before the leaching is completely removed. When painting in a bathroom, allow the paint to dry thoroughly before using the bath or shower.

Surfactant leaching commonly occurs outside under eaves, on soffits, balconies and covered patios where moisture can collect. When surfactant leaching occurs outside, flush with clean water immediately before the stains have sufficient time to set up or harden. You can also scrub the surface with a soft brush. Light scrubbing with a soft brush is acceptable. If you can't remove the stains this way, repaint in more favorable weather conditions to allow the paint film to cure properly.

If you're painting where moisture occurs, you'll likely have to deal with surfactant leaching at some point, but there are ways to prevent it.

• Follow the manufacturer's instructions to ensure proper preparation and application, including storing paint at the right temperature and painting at an optimal time if painting an exterior surface.
• Properly ventilate the space to ensure the paint cures properly before using it again. Ventilation is essential in bathrooms where humidity and moisture are constant occurrences.
• Use paint formulated explicitly for humid environments.

These same steps apply to prevent surfactant leaching in bathrooms, but you may want to wait a few days before using the space to allow the paint to cure fully. Don't forget to ventilate your space between showers to dry out the space between uses, which will minimize surfactant leaching.