Anyone Know the Straight Dope on Latex Paint

Hi Everyone

I was wondering how bad/dangerous latex paint is in its liquid form, from an environmental perspective. I know that most people clean their brushes etc. into the sink, which puts the liquid paint into the sewer system. Now I don’t know what the effects of this are on a large municipal water treatment system, but one would hope that these systems are designed to handle such a common material.

However, I have well and septic, which means that when I clean brushes, the latex goes into the local ground water. That seems a little different to me than allowing fancy, expensive equipment to manage it- but perhaps I am wrong.

SO- given the expense of good brushes and such, and the fact that I am usually disappointed in the performance of the cheap ones I can just throw away, I prefer to continue cleaning the stuff in the sink (or the yard, but there the latex ends up in the groundwater anyway) but I’d like to know what information the folks here might have.

Rinse water from latex paint is, indeed, best handled by a sanitary sewer system. In areas where this is not available, regulatory compliance requires cleaning tools in a bucket, and disposing of the rinse either by transportation to a sewer system, transfer to a waste disposal firm, or – in some areas – pouring out into a flat area with natural ground filtration like gravel. I’m not a fan of that last one, but it’s a possibility, I guess.

Better: a series of small rinse containers, each rinsing out the residue of the last one. Let the paint particles settle until the water is clear; I think this can safely go into your septic tank, and the paint at the bottom will dry out and can go into the trash. You’re right not to want to rinse directly into the septic tank; ground water aside, that stuff can gum up the works, and may kill the bacteria that make good septic systems work.

You will notice the characteristic sweet odor of latex paint. It is due to ethers and ether esters that are relatively toxic. See I know they aren’t good for people. I would think that small amounts might kill some of the bacteria in a septic tank, but would be overwhelmed in the end. As for the paint solids, they are polymers of acrylic, styrene, butadiene, etc. and mostly biologically inert. The pigment is mostly titanium dioxide and silicas, again non toxic. The government has provided us with unjustified high levels of protection from paint pigments at our expense.

There are also mold inhibitors which will take a toll of the bacteria. All in all, latex paint isn’t as safe as it have been sold to the public. Like many other useful things, you are much safer if you read and follow directions. Yes, it does say use good ventilation. Open the window.

Bacteria are quite opportunistic. They might even eventually chew up the polymers.

Unless you are painting your whole house at once, the rinse water will not gum up a septic system. I had to help my father put in our current system almost 40 years ago. It’s never been pumped out, or otherwise required any work, and we (my father when I was younger, and now me) have never had to do any maintenance on the system, despite using latex paint for the interior walls for all those years. In that small a quantity, it’s non-toxic. In large quantities, like a professional painter might encounter if he brought home all his wash water, I wouldn’t be at all confident. But in normal household quantities, I’ve never heard of anyone encountering problems.

Over the years, the EPA has been mandating toxic ingredients out of paint steadily, so that now normal latex paint is pretty environmentally benign.

ETA: thelabdude has a more thourough take on toxicity, above. But also note what he said about “unjustified high levels of protection”. The EPA has probably overdone it. Follow the directions on the can and you’ll be fine.

I got latex paint in my eye. I flushed it like crazy, but I have a headache. :confused: Should I be worried?

Thanks everyone

I have tried cleaning into buckets, but I have found it doesn’t work as well.

But probably the thing to do is an initial clean in a bucket, which will get most of the material off the brush and then finish under running water.

Rollers I just throw away.

99 times out of 100, symptoms like that will go away in a day. If you are still having symptoms today, see a doctor. If they’ve gotten worse, go to the ER. If the symptoms are gone, give it another day, then assume no worries. I hope that was sufficiently helpful, and you wind up OK.