No!
The resounding answer to this question is no! There may be times when you accidentally pour some down the drain or forget to remove it from your brushes before washing, but you should always be conscious when using paint thinner, and dispose of it correctly.
Not only can disposing of paint thinner incorrectly harm you and the environment, but it can result in fines too. Depending on where you live, there may be laws in place to discourage disposing of paint thinner down the drain, and if you do, you can be forced to pay for your mistake. That is reason alone to dispose of it correctly.
The best way to dispose of paint thinner is to find your nearest hazardous waste recycler. This can be accomplished with a quick online search, and there is usually such a facility at your nearest fire station. Make sure that your paint thinner is in a sealed container when you are transporting it, and then drop it off.
The exception to this is when your paint thinner container is empty. Make sure that it is as dry as possible inside the container, and you can throw the container out with your household garbage.
But, Why Not?
Pouring paint thinner down the drain can not only damage your drain, but it can damage the environment too as it will eventually end up there. If you do pour paint thinner down your drain, there are a couple of things that you can do.
The first, if only a little was poured down, is to flush the drain with hot water and soap. Mix up some soapy hot water and pour that down the drain. If you still notice a strong paint thinner smell after doing this, try it one more time, letting the soapy water sit in the drain before flushing again.
If the smell persists, try removing the u-bend under your sink and let the drain air out. You can also clean out the drain with alcohol. This is also recommended if a lot went down, and you can retrieve some from the u-bend. Always wear gloves when you are doing this.
Impact of Paint Thinner on the Environment
Not only is paint thinner extremely flammable, but it is poisonous too. Granted that paint thinner will be watered down by the time that it reaches any waterways, but that does not mean that it is still not harmful. When paint thinner gets into the waterways, animals are consuming it, plants are absorbing it, and it is in the water system.
This can eventually mean plants being killed off, contaminated water, and poisoned sea life. And, that is sea life that we may be eating.
No matter how much of a rush you are in, always dispose of paint thinner responsibly.
Paint Thinner Is A Fire Hazard
Paint thinner is flammable, in fact it can spontaneously combust or catch fire when it reaches the auto-ignition temperature of 245 degrees Celsius or 743 degrees Fahrenheit, according to Firefighter Insider.
Paint thinner also has a flashpoint of just 104 degrees celcius. For this reason, you should never work with paint thinner around flammable options, in extreme heat, or around smoke/fumes.
