How Do You Know When You Need Guano Cleanup?

Dealing with a bat infestation may be the most difficult problem a home or business owner will ever face.  How to deal with the bat guano (bat droppings) that comes along with an infestation can be an equally overwhelming task to contemplate.  With over 20 years of bat exclusion experience, we have learned when to tackle it and when to leave it alone. How can you as the property owner know when you need guano cleanup?

Where To Begin

First, you have to get the bat colony excluded.  It doesn’t do any good to address guano in an attic until you know the bats won’t be coming back to keep the cycle going.  There are extreme cases that require some guano clean-up to even get access to the bat exclusion areas.  Recently we received the following from one of our seasoned technicians on the job:

“How often do you have to clean up guano on the roof before you can comfortably work on setting exclusion devices.? I did this inspection last week. There was so much guano at the main entrance I didn’t feel safe to work around it till I remediated it. This is within a couple miles of the Ohio River in Kentucky. The Ohio River Valley is supposed to be the worst place in the world for Histoplasmosis. So, I told him I would come back to do the job with the guano cleanup equipment.” -John Martinez

As you can see in the photos he took, common sense and safety required guano to be cleaned up before he could continue with the exclusion.

What To Consider Once the Bats Are Gone

Recently, I had a client come to the realization that they had a major bat problem that likely had been there for 7 plus years. All the signs were there, but they had been attributed to other things… maybe mice, assuming and treating bed bugs not bat bugs, and a musty smell that could have been caused by the damp environment of their lakefront property.  When the realization hit that this was definitely a bat issue, one of the first questions was “How do we know if we need guano cleanup too?”

My answer is the 3 S’s:

  1. Smell
  2. Structural Damage
  3. Staining

Let’s look at these 3 factors one by one.


The best way I can describe the smell of bat guano is a musty smell with a hint of ammonia.  I’ve heard other people use the words pungent, acrid, and foul.  As simple as that sounds to identify, sometimes we get used to the smell of the place where we spend a lot of time. We have had cases of bad smelling guano pileups where the homeowners were pretty immune.  If you aren’t certain, it’s a great idea to bring in a trusted friend or relative who will give you an honest opinion. Our technicians are very good at identifying the scent, if you want a professional opinion.

Structural Damage

Bat guano and urine can cause a lot of damage.  It can erode drywall and ruin insulation.  Of course, if there has been damage to the structural elements of your home, excluding the bats, cleaning up the guano, and repairing the damage is the best route to go.  This isn’t the cheap route, but it is the safest and best route in the big scheme of things. There is a good chance your homeowners’ insurance may cover this, so it is a great idea to look into it.


Unfortunately, staining is common with a bad infestation.  It is potent enough to soak right through sheetrock.  Sometimes, a new paint job can cover it for a bit, but in the end, usually the guano needs to be removed.

In What Situation Do We Leave Guano Alone?

If your bat problem has been remediated and you’ve read the above information and it does not seem to apply, you might be one of the fortunate ones where we would advise doing nothing more after the house is safely sealed up.  It might seem gross to think of sealing guano in the wall, but don’t worry, it will dry out and become a nonissue.  Besides sparing expense, it won’t stir any of the spores that cause histoplasmosis into the air you are breathing.

Uh Oh! I Need Help With Guano Cleanup

If you read the above 3 S’s and have come to the conclusion that you have a guano problem, you are probably wondering, “What should I do now?” The best thing to do is hire a professional to come in.  Histoplasmosis is not something to mess with.  Technicians will work in full hazard gear with respirators. They will safely dispose of guano without stirring it up. It will be a huge relief once it’s handled, and you can focus on any repairs that need done.

In summary, use our “3 S” assessment (smell, structural damage, staining) to determine if you have a guano situation that needs to be addressed.  If your answer is “I do” then please get professional advice on submitting a claim with your homeowners’ insurance.  Our customer service representatives have been trained to know how to do this successfully, so give us a call! 877-264-2287

bat technician removing guano

Your Local Bat Expert,

Michael Koski

Get Bats Out Owner and President Michael Koski
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  • Andrew brumbles

    April 16, 2023 | Reply

    Guano what if their only a little bit scattered in one end of attic would you recommend just leaving it.

    • Tori Bruce

      April 18, 2023 | Reply

      A little scattered guano (bat droppings) is not a major concern. It will dry up on it's own. The problems show up if it accumulates, it can lead to disease (histoplasmosis), damage your attic and smell.

  • Reggie Monce

    October 2, 2019 | Reply

    Is there anything that removes the odor of the bat’s marking fluid? Something not flammable or dangerous to the human residents?

    • Tori Bruce

      October 3, 2019 | Reply

      We have found pet odor enzymes to sometimes be effective. Hope that helps!

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