Tip #22

Boric Acid is the Best Roach Killer

Written by on January 18, 2013

WARNING: Any product that will kill a roach, is usually somewhat dangerous to humans.Therefore, be mindful of pets, babies, and tenants when treating your rental property.

Boric Acid

I’ve tried almost every roach-killing chemical out there and the winner seems to always be Boric Acid – which is an inexpensive do-it-yourself product that can be found at most big grocery stores and all hardware stores.

In my opinion, Boric Acid is the best roach killer because it works. period.

Harris – My Favorite Brand

Roach Killer Powder, 16 ozHarris Roach Killer Powder is my favorite brand because it’s cheap and seems to work faster than other brands. When I use it, my roach problems go away – which is all I really care about. The tablets also come in handy.

The reason I use Harris, is because I’ve found that other brands sometimes dilute the product with filler, making it not as potent and less effective.

One easy trick is to mix the powder with sweetened condensed milk until it becomes a sticky paste.  The paste is an edible poison that the roaches cannot resist.

When my tenants complain about roaches, as a measure of good faith, I usually buy some Harris Brand Boric Acid (which comes in tablet and powder form), and spend 10 minutes putting it all around the house – anywhere that I think roaches might be hiding.  The powder comes in handy for laying a line of poison or squeezing it into holes and hard-to-reach places.

If there are too many roaches already, and an infestation is already well underway, I just simply call an exterminator and make my tenants pay for it (per the lease of course).  Boric Acid usually works in 1-5 days, but if the problem is an urgent one, exterminators will treat the property with high-powered chemicals and “bombs”.  Just be mindful of your tenants and pets before going nuclear.

Learn More

Guide to Roaches

Read my other in-depth guide that describes How to Kill Roaches in a Rental Property

  • Other roach-killing products
  • How to know when to call an exterminator
  • Useful lease clauses that address roaches and infestations
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31 CommentsLeave a Comment

  • Jim Davis

    I have spent a great deal of time in property management. We tried everything until we finally found a boric acid paste professionally made by landlords. The paste had been around for many years and yet we hadn’t heard of it. It is called MRF 2000 and it is the best thing we have ever used. Instead of spraying all the time, we can now treat an entire complex with one application and get an entire apartment building roach-free; what a relief.

    • Lucas Hall

      Hi Jim,
      Thanks for your feedback. The MRF 2000 seems similar to the paste I describe. But the fact that it already comes pre-packaged, and I don’t have to mix it is very nice!

  • joe

    unfortunately for me, I live in california, and I am legally not allowed to charge the tenants for bringing an exterminator. It is my responsibility. Damn..

    • Lucas Hall

      Hey Joe,
      It’s great to meet you. Thanks for your comment, but it’s not entirely true.

      Here’s my understanding of CA laws:
      1. The landlord must provide a clean, pest-free home when the tenant first moves in.
      2. At any time during the lease, a landlord must take action to get rid of any pests that show up.
      3. However, the burden of paying for the pest removal falls on the person responsible for pests in the place. If your tenant’s living behavior causes a mouse and roach infestation, then you still have to take action to rid the house of them, but you can charge it back to the tenant.

      I’ve never seen a law that requires the landlord to pay for pest treatment under all circumstances. What if you have a hoarder tenant? Please prove me wrong if you can cite the statute.

  • yudi

    I live in indonesia it is hard to find it so you can advise me how i get it ?

  • Marilyn

    We are battling a roach infestation at my elderly Mother’s home. She continually calls the exterminator out, they spray but it never gets rid of them. It is a “never ending story”. I feel like they are taking advantage of her. I’ve also read that exterminators have changed the chemicals in their product because if they kill the roaches, they do not get called back, therefore business is not good. Do you have any special instructions to go by if we decide to try this in her home?


    • Lucas Hall

      Hi Marilyn,

      I would use the powder boric acid and squeeze (spray) it into every nook and cranny. Then make a paste out of it, and put it on the insides of your cabinets wherever you are seeing roaches.

      I give some more details here; http://www.landlordology.com/how-to-kill-roaches/

      If that doesn’t work, you may have to “bomb” the house, which would involve your mother moving out for a few days.

      Also, you could try a different pest removal company. Some are better than others. Try searching Angie’s list for a A+ ranked company that has lots of experience with roaches.

  • gabriel smit

    your 100% on target with boric acid. with diatomaceous earth, it will kill most household critters like cockroaches, fish moths, crickets, fleas, ticks and bed bugs.
    it is cheap, less toxic than table salt and works like a bomb!

  • EJ

    Just moved in to my sisters house roach free. I used to live in an apt Complex with roach problems. I took forever to move out cuz I wanted to make sure that the stuff I took into her houdr were roach free I saw four roaches already. What sgould I do? My sis is freaking out cuz she hates roaches.

    • Lucas Hall

      Hi EJ,

      Roaches are super sneaky, and it doesn’t surprise me that they found a place to hide during the move.

      Anyway, check out my other How-to guide about roaches. I think you can definitely take are of it yourself with the right poison/tools. Otherwise, any of the major pest control companies would happily get rid of them for you.


  • April Fairfax

    Want email

  • Gabriela

    Hi, I’ve been living in my home since last August. When the temperature changed and got warmer, we started noticing roaches. I have children. If I started the boric acid process how long would it be until it’d be safe for my family to come back home?

    • Lucas Hall

      Hi Gabriela,

      I’m not boric acid scientist, but the trick is to squirt the powder into the nooks and crevasses in your home – far away from the kids and pets. If you use the tablets, just put them where you are seeing roaches, and make sure your kids can’t get to them (the same as you would treat mouse traps).

      In this guide, there’s a video to show you how to make a paste that will stick to cabinets.

      As long as the powder or tablets are out of reach, it should be safe for you to live there during treatment.

  • Becca


    I am a tenant renting in Chicago. Recently I found roaches in my apartment. I was shocked because I am an extremely clean person. The tenants living downstairs moved recently, and I believe they are coming from there. I contacted my landlord but they said it is my responsibilitie after 30 days of moving in. How can I treat this problem if it isn’t just a problem in my apartment?

    • Lucas Hall

      Hi Becca,

      If I were in your shoes, I would politely approach the neighbor and say “Hi there, I’m Becca and I live above you. I noticed some roaches in my apartment, and I was going to hire a pest company to exterminate them. Since we share walls, they are probably in your unit too, and I was wondering if you wanted to split the cost of extermination for both of our units. It would be cheaper if we go-in together.”

      Other than that, you’d have to prove that the roaches are being caused by dirtiness or neglect from your neighbor, and then seek damages from them. You could also talk to a lawyer, about how best to deal with your neighbor. Further, you could also try some of the remedies in this guide: http://www.landlordology.com/how-to-kill-roaches/, which would be much cheaper than an exterminator.

      I hope that helps some. I’m sorry you’re having to deal with roaches.

  • Emma

    Hi there,
    This sounds like an awesome product and I want to try it out but I’m pregnant and worried about the chemicals. I would of course not be handling the product but is it safe to have in my house? In which form is safest? I’m thinking the paste you say is efficient might be better then a powder that can be airborne? Any thoughts and tips are appreciated. Thanks!

  • Abel

    I just got the boric acid, I guess I was expecting next day results, but maybe previously using a diff spray they been hiding and now came out with a vengeance, I just laid the acid 3 days ago how long before we see results, and also what are the ways to make paste. Thank You

  • Cathy

    Hi there,
    I had some squatters living next door. Our homes are not connected. These people were NASTY!!! They finally got kicked out but we started seeing roaches when they were living there. Initially on our fence & the side of our house in record numbers. We have called an exterminator who has treated the house twice. We are slated to call them again because after putting down a lot of boric acid in the kitchen which is where we see them a lot, they have not taken residence in my bedroom!!!!! I’m not sleeping to say the least. I’m afraid they are going into my toddler’s room next. Please help me!!! I want those bastards gone. By the way, the house next door is not vacant & red tagged. I’m assuming they are going to continue to come over the gate & into my house. Please please help!!!! Thank you!!

    • Lucas Hall

      Hi Cathy,

      When the roaches are that many, you’ll continue to need to work with an exterminator. Further, I suggest using the powder boric acid and laying a barrier on that side of your house. Also, open up all your outlet covers and seal any gaps with spray foam, and boric acid. If you can seal up your house, the roaches will have a hard time getting in.

      Many pest control companies also have a year long subscription, with a guarantee. The guarantee will cost you upwards of $400, but it’s better than roaches! Plus, you might be able to convince the owner of the next door property, to reimburse you.

      Good luck!

      • Cathy

        Thank you for your comment. I actually meant to write the house next door is vacant & red tagged. Squatters were thrown out!!!!! Thank you God!!! The house is in fourclosure. I’m sure it’s still infested. But I’m hoping the roaches stay there now that it’s getting cooler out but I’ve seen some bold ones crawling in at the top of my side door. I do have a contract with the exterminator & do the above. I just feel like we are never going to be free. The storm drain is also in front of my house right off the curb. Could that also be causing a problem?

        • Lucas Hall

          Hi Cathy,

          Hopefully the storm drain doesn’t have any breaks or cracks that might allow them into the house. Otherwise, if it’s sealed, they are not likely to come through the plumbing traps which are sealed with water.

          That’s just my understanding. I’m not a pest professional. It would be worthing asking the exterminator next time.

  • Lora Sledge

    Hi, I’ve been living in my downstairs apartment since July 2014. I have sprayed, put down roach traps, and gel my apartment, still no help! My neighbor above me is filthy anfd tne roaches are coming from up there, I have bought some Harris Boric Acid Powder. I need to know what to do because the roches are coming from my ceiling and the top of the walls!

    Please help!

  • Stephanie

    Hi Lucas,

    Thank you so much for the great tips. I currently rent an apartment with my 3 1/2 year old son. We are moving from our current location to another location within the same complex. There was an infestation that was so bad that they evicted the people in the unit that was the source of the problem (which happened to be right below our unit) the day of the inspection.

    The leasing office told me (unwillingly) that there are a couple of units in the new building. We get the new unit keys Nov 7th and have until Nov 9th to move out of our current unit. I’m not OCD, however when it comes to bugs I am now. If I spread the powder along all the baseboards as soon as I get the keys (Friday) will it be safe to have my son’s toys moved over by Sunday?

    Thank you so much for any suggestions you may have.

    • Lucas Hall

      Hi Stephanie,

      I don’t recommend putting boric acid on any surface that a baby could touch. I’m not an exterminator, but I think it works best when squeezing the powder into the cracks or areas where the roaches are entering the unit. If there are cracks under the baseboards, you can squeeze it into there.

      Or, check out my other How-to guide for making a paste out of boric acid:

      If you have any other concerns about the product, you should contact the manufacturer: http://pfharris.com/

  • Janacarles

    where Can I get this Harris boric acid or tablets… Thank you

    • Lucas Hall

      Hi Janacarles,

      Just click on any of the links in the article above and it will take you to the Amazon page where you can buy it. You can also find it at most hardware stores, or even many grocery stores.

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