Hi Inspirations, we have repainted the bathroom a few weeks ago, and have noticed that there are streak marks appearing on the walls after someone uses the shower. I have tried to wipe the marks away but having no luck. Are you able to offer any help? Thanks.


Hi there, thanks for reaching out! It sounds like the issue you are encountering is called “surfactant leaching”. It’s a pretty common issue in areas of your home where there is lots of moisture, like a bathroom or laundry. Check out the info below on how to deal with surfactant leaching, but if you’re unsure if this is the problem you are experiencing, head into your local Inspirations Paint store with a picture of your problem and the team will be able to help you out!

What is surfactant leaching?

Surfactant leaching is the appearance of spots or streaks that appear on a freshly painted surface. The marks can sometimes be soapy, sticky or oily; and be anywhere from a white to brown colour. Surfactant leaching can occur in both interior and exterior areas of a home where excess moisture may be present.

How is it caused?

Bear with us as we get a little technical! Paint contains ingredients called “surfactants” which are critical to the make-up of paint. Surfactants are designed to slowly evaporate from the paint during the curing period without effecting the appearance of the painted surface.  

Surfactant leaching is caused when the freshly painted area has not been given enough time to cure, and is exposed to adverse conditions that cause the surfactant leaching to occur. The surfactants within the paint are drawn out of the paint quicker than designed to, and they rise to the surface of the paint, leaving a watermark-like mark on the paint.

Surfactant leaching typically occurs in household interiors where there is an increased amount of moisture; such as a laundry when a clothes dryer is being used, or a bathroom after the shower has been used. Outdoor areas such as eaves and awnings where dew and moisture collects is also a common place for surfactant leaching to occur.

Poor drying conditions where there is not enough air circulation or ventilation, areas where the substrate is cold, cool air temperatures or higher humidity levels all contribute to surfactant leaching occurring.

Solving the problem:

The great news is that surfactant leaching is purely a cosmetic issue, and does not cause any damage to the actual coat of paint or substrate.

If surfactant leaching occurs shortly after the surface has been painted, allow for the surface to completely cure (refer to the information on the paint can for appropriate cure time) before cleaning down the surface with a detergent-based solution (Selleys Sugar Soap is great for this). You may notice that the issue may occur a few more times before the surfactants have been fully expelled from the paint.

If the streak marks have been left on the surface for a longer period of time, the surfactants may have stained the paint and therefore if you decide the marks on the wall are a problem, you will need to re-paint the surface.

If an exterior surface has experienced surfactant leaching, normal weathering will typically remove the stains naturally.

Preventing the problem:

Follow these helpful tips to prevent surfactant leaching from occurring:
- Ensure the area you are painting has adequate ventilation throughout the drying time
- Avoid painting in less than desirable painting conditions (eg. if rain is expected or if you are painting in the afternoon and the evening or overnight is expected to be cool or damp. If you need to paint an interior in cold or wet conditions, check out this article for some tips on Painting When It’s Cold & Rainy)
- Allow freshly painted areas to fully cure before exposing to adverse environmental conditions
- Avoid applying water or moisture to a water-based coat after the coat has dried
- Avoid using a clothes dryer in a freshly painted laundry until the paint has fully cured (we suggest moving the dryer to another room to use while the paint is curing!)
- Although it is difficult to not use a bathroom while allowing the fresh coat of paint to fully cure, ensure adequate air ventilation is present when using the shower recess to assist in preventing steam and humidity to impact the curing period.

If you think surfactant leaching may be an issue in your home, we recommend taking a photo of the issue and heading into your nearest Inspirations Paint store to have a chat to our expert staff who will be able to assist you in solving and preventing this problem from occurring.