Why is foam coming out of my gutters? 4 Possible Causes – Should you be concerned?

By Tom •  Updated: 03/29/22 •  3 min read

During or after a rain you might notice what looks like white foamy suds spilling out of your downspouts or soapy foam that has pooled around downspouts. Don’t worry, a foamy gutter or downspout isn’t cause for concern. I’ve researched the possibilities and it could be any one of a number of 4 possible explanations, none of which should make you worry. 

The water from my downspouts are making foam puddles

So why is white foam coming out of your rain gutters? 4 Possible Explanations

Here are all of the possible explanations I was able to find for why you might be seeing sudsy rainwater coming out of your downspouts:

  1. Recently cleaned roof. Various soaps or bleach might be used and if it hasn’t rained much or at all since your roof was cleaned, there might be some residue remaining. This could potentially cause foaming in your gutters. In this case, it should resolve itself after a few rains at most.
  2. Recently installed new roofing shingles. I’ve heard that when some shingles are manufactured, soapy water is applied in order to cool down and keep separated the shingles. It’s possible, again, that some of that residue might remain on your new roof shingles. When it rains soon after the new shingles are installed on your roof, some foam could be produced. Again, nothing to worry about here, it will go away after a couple of rains and won’t harm your house or plants.
  3. High pollen count. When there is a lot of pollen floating in the air it will get on everything. That pollen will stick to your roof along with other dust and particles. When it rains, that crud will flow down your downspouts and create the foam which might look a bit more green or yellow as opposed to white. Perfectly natural.
  4. Sap or dead organic matter from trees, plants and leaves. Decaying organic matter produces proteins. This organic matter can cause similar foaming on the edges of bodies of water or on paved roads when cars mix up water, pollutants and organic matter during a rain. If you have a lot of pine trees around and above your house, it’s possible for the sap to drip down on your roof and that sap has some soapy elements to it. You can see this effect sometimes directly on sappy trees during a heavy rain. When it rains, the water mixes with the sap and other stuff which can become foamy.

What should you do about foamy gutters?

Nothing. I’d recommend to just let it go because once it rains a couple of times whatever is causing the foaming should dissipate and eventually go away completely.

There you have it. See? While the white (or yellowish or brownish) foam pooling next to your gutters It can be a bit unsightly, all of the explanations for the foam are pretty innocuous and will go away on its own as you get more rain. Do you have any other explanations for foam coming out of your downspouts? Get in touch.


A few years ago I bought my first house. It’s 100 years old. It’s clearly had a history of less-than-professional DIY handymen/women. And APPARENTLY you’re supposed to actually put work and money into it if you don’t want it to look terrible or water to rain down on you while you’re sleeping. About YouTube Facebook Twitter Pinterest Instagram