Disposing painting waste

Disposing of dirty paint water – What not to do

Painters wash their tools frequently, especially after jobs with many colour changes. Sometimes there is no access to water, especially when painting in new construction projects. When water is plentiful, some painters wash their tools outside with a hose without considering where the wash water is going. As an environmentally friendly contractor, Ecopainting places great importance to the issue of paint waste.

Pouring paint and paint contaminated water into the storm water drainage system is environmentally irresponsible. Painters need to rethink the common practice of washing their tools outdoors with a hose. The contaminated water enters the storm sewers and pollutes our lakes and rivers. In most municipal jurisdictions this antiquated practice is also illegal. From the City of Markham website:

“The Storm sewers are the grates you see along the streets and are designed to collect rain water and snow melt only – nothing else! This system is in place to prevent flooding in our streets and to re-direct the water to a water source. Water that enters the storm sewer system flows directly into our ponds, streams, rivers and lakes without being treated.”

If you absolutely must wash your tools outdoors, do not use a running hose. Use a small amount of water and clean your tools in a bucket. When you finish cleaning, keep the water and reuse it to wash your tools again or to soak them overnight. When it’s time to dispose the water, use a sink that goes to a water treatment facility.

When water based paint waste enters the waterways

Paints contain solid pigments that can increase the turbidity of water. In addition to making the water “muddy” and unsightly, they can cause particles to clog the gills of fish, and restrict their ability to breathe. Increased turbidity can also block out sunlight and reduce photosynthesis in plants. Paints also contain several biodegradable substances. As they break down, they can reduce the oxygen level in the water making it difficult for fish and other organisms to survive.

When solvent based paint enters the waterways

Solvent based paint waste contains many organic solvents and compounds. These substances don’t mix well with water. When they eventually break down they deprive organisms of the oxygen they need to survive. Solvent paints can contain lead, mercury, zinc and chromium. These heavy metals can contaminate the sediment and poison the food chain. The toxic ingredients in solvent based paints can cause tumors to be formed in fish and other water organisms.

Tips for Cleaning and Maintaining Paintbrushes

The good news is that the majority of the paints we use today are water based. Whether using water based or solvent based paints, the basic principle remains the same: use as little water or thinner as possible and and reuse it when you can.

In this video, Scott Burt from Topcoat Review, demonstrates a simple wash system for a paint brush.

Practices to Follow when Cleaning Brushes and Rollers

Cleaning Brushes and Rollers from Water Based Paint

Transfer as much paint as possible back to the paint cans by squeezing the brush. Remove more paint by painting a surface with it until almost dry. To clean a roller use a 5 in 1 tool to squeeze as much paint out of it. That technique removes up to 90 percent of the paint. Before washing them, prewash them vigorously in a container with a small amount of water. A five gallon bucket works great for this purpose. Re-use this paint water for the first wash the next few times and eventually let the solids accumulate at the bottom. Dispose as solid waste. A three bucket system of progressively cleaner water works well. If you don’t have the space for this and you are in a hurry, always wash in a sink and not on the lawn.

Everyday Tips

  • Pre-wet your brush and roller with water before using it.
  • Use tools that are easier to wash such as the newer chinex bristle brushes and microfibre rollers.
  • If you have not finished using a colour, wrap your tools in plastic at the end of the day. This will keep them fresh for the next day.
  • Before washing your tools, use them for the first coat of the next colour, when the colours are similar. Before the final coat, just give them a quick rinse as the new colour worked itself into the tools.

Cleaning Brushes and Rollers  from Solvent Based Paint

A few years after the original blog was written I am happy to say that we don’t use any solvent based paint. Occasionally we need a solvent based primer or a specialty metal coating. Most of the time we use inexpensive brushes and rollers, we let them dry and dispose them as solid waste.

If you are using your tools for same or very similar colours wrap them in plastic and keep them in the freezer. They will stay fresh until you need them again.

During the Toronto winter leave them wrapped outside or in your trunk. Left outside paint brushes and rollers wrapped in plastic can keep fresh for days. Read more environmental tips.

Note: when you need to dispose dried up tools and solvent waste, contact your municipality for their waste disposal policies

What To Do with Leftover Paint?

Paint contractors constantly deal with the issue of leftover paint. We order for a project and despite our efforts at accuracy, we end up with extra paint. If it’s a small amount we leave it with the customer for future touch ups. If we have leftover gallons of paint we organize giveaway events at our shop and share our leftovers with the community.

If you are a DIYer and you have leftover paint, drop it off at a retailer such as RONA and Home Depot.

If you have unopened paint cans you don’t need, contact Ecopainting at 416 733-7767. We will add it to our inventory for our next paint giveaway event.We discussed the washing of paint brushes and rollers because these are the main tools our painters use. Painters washing their spraying equipment can follow the same basic rules about paint water waste.

Update July 2019: after we promoted our leftover paint giveaways, we seem to be getting a good number of calls for any leftover paints. We are happy to donate any paint we don’t need, just make sure to call ahead and check our inventory and available colours..

This blog was first published on June 12 2013. Since then it was updated on April 1st 2017 and July 27 2019.

27 thoughts on “Disposing Paint Waste”

  1. Hello I have a question about water based paints without colored pigments (white).

    Is the water used for washing brushes safe to dispose of down the drain?

    Thank you.

    • Hi Carla, depending on the water treatment capability of your municipality, it’s always better to dispose any water based paint wash water down the drain. Having said that, try to wash your tools as much as possible in a container like a bucket, so you have more control of the water that you use. In fact a series of smaller containers with progressively cleaner water is best. Thank you for your question.

  2. I had some paint left outside to dry before discarding, unfortunately it rained and I never brought it in, now the 2 cans are full of water. What is the best way to dispose of them?

    • Hi Judy. It may not be a bad idea to let it settle for a few days and when the water is fairly clear you can empty it down the sink. I am assuming your area’s water treatment system can handle that. Then let the cans dry again and dispose as solid waste. Maybe add a little cat litter to it to accelerate the drying. I hope this helps.

  3. Thank you for the simple, common sense solutions to dispose of paint properly. I paint throughout our house often, and I’ve been frantically searching for solutions to dealing with leftover paint and paint water (after cleaning tools). The information you provided is much better and more helpful than the information I’ve found on websites of paint manufacturers and retailers. I love animals and I love the environment. Thank you for caring.

    • Hi, I’m surprised that this site doesn’t offer up suggestions for making home made paint-water filters, even for filtering out particles, Some artists using paint suggest a filter made up of crushed charcoal (others recommend using activated charcoal). I’m searching to see if some fabrics can act as useful filters and am doing an experiment using facemasks as a filter.

      • Interesting point, early filtering should help with the waste water painters create. However, I am not sure it can be as good as how some municipalities deal with waste paint water. At least at the scale that a painting contractor would be using it. For a homeowner or an artist creating way less wastewater volume, I could see the need. Also for jurisdictions not doing a good job with their waste water treatment systems. If you find a resource, or find a way to do this, please share with us. We can all benefit from your knowledge and ideas. Thank you so much for contributing to the discussion.

  4. I live on a septic system, therefore I can’t dump paint water down the drain…any suggestions on how I can dispose of it? Thanks!

    • Thank you for your question Livi, sorry about the late reply. I would collect the paint water in containers (5 gallon pails work for this) and let the solids separate and go to the bottom. With some water paints this will take some time so try not to move he container. Use some of the top water for more washing or other purposes. After removing the cleaner water, the sediment will eventually dry. A painter I met here in Toronto had this great idea. He was creating artwork with concrete and was using the paint water instead of regular water to mix the concrete. I think that’s a great idea for a homeowner to do this as you can create colourful concrete lawn ornaments or planting pots.

  5. A huge shout out to you guys! This is a very real issue with many painting companies. They need to become more responsible regarding paint waste and dirty water contaminations of our environment. There is such a simple solution and I cannot imagine why this isn’t common practice with all painting companies. Thank you for sharing your thoughts and suggestions on this topic!

  6. Thank you for the very helpful information. Most of us try to do what is environmentally correct but such advice is frequently difficult to come by. Your advice was useful and explained why it should be done that way using facts and scientific knowledge. Much appreciated!!

  7. Thank you for taking the time to inform DIY such as myself, in Northern BC. I am a grand father: we MUST do a much better job of reducing waste, disposing of it eco-responsibly; — we are all benefitting from your guidance and generosity. As a retired home-builder, I hope you are having a good year with your business operation, and getting LOT’s of work 🙂

  8. So, what I’ve gathered here is, it is better to dump waste water down the toilet or to clean brushes in sink. I know “professional” painters that use outside hoses, faucets etc. straight into the lawn or mulch. Buckets of waste water dumped in back corners of Homeowners’ lawn or alley.
    What I would love to see is some sort of 3 bucket or 3 layer 1 bucket, portable brush cleaner. The way I picture 3 layer: 2 gallon bucket, dome cover, slot where paintbrush cleaning comb would be attached inside, spray nozzle spraying across the comb, across lip of bucket is 3d printed shallow funnel w/ spray nozzle install area aimed @ angle so water will funnel, filter layer ….. remember the old stackable food dehydrators? I want 3d printed, layered sections that pc together like that. designed for standard 2 or 5 gallon buckets. ….. Anyway….. with that in mind it should include 3 filter layers below funnel using coal or lime or whatever filters it clean. The water only needs to be clean enough to wash brushes throughout work day. External (internal?) pump would be at bottom pulling water to feed back up to spray nozzle. It would need to be portable, maybe the dome would turn over and create a sealed lid for transport. Take it to the toilet and flush filtered water off to your local municipality (if they can handle it) and trash the solids.

    • Great concept. I wonder if someone somewhere has a working model that comes close to this. Maybe there is a market for it for you to pursue. I am worried that with our latest disposable everything mentality (food delivery, masks, sanitizing parts, etc), I am worried that all this becomes trivial. I hope not. At the end it is up to the user to be environmentally responsible to use any equipment available. Thank you for the ideas and contribution.

  9. Didn’t see any reply about how to dispose of paint wash-water if one only has a septic system. Any comments? Dig a hole in the back yard and pour the waste water in?

    • I do not know how to with a septic system. One idea is to let the solids collect to the bottom of a container and dispose of them as solid waste. This will take a long time to happen. Someone I know uses the paint water when making concrete and he makes decorative garden objects with it. Your local government should have some information.

      • Yes, it would be good to know some basic guidelines for people on well and septic systems. Especially if wanting to paint in the winter (summer we want to be outside)… I am always thinking of how to do it but end up waiting until nicer weather. Cannot find anything on internet about it either. We have some big painting projects that would be nice to get done over the winter months. 🙂

  10. I don’t see what’s wrong with dumping latex paint water into the dirt of an alley, where it can filter down through the sand, rather than down the drain where it will clog pipes and then to the water treatment plant which may not be able to remove all chemicals which will end up back in the waterways. Not sure what the basis is for that idea?

    • A good water treatment system should do a better job in filtering leftover paint water than the pouring it in the waterways. I suppose it depends on how good the treatment plant of the municipality is. These are the environmental suggesions anyway and as with anything else, there might be enough research and studies to reach these conclusions. Thank you for your question Genie.

  11. Hi! I really appreciate all the insight on this, especially as a beginner. I did have a question though. I’ve been looking everywhere for an answer to this and I can’t seem to find any.
    Is there any way to reuse the acrylic paint sediments/leftovers in paint water? I’ve looked up all the ways to properly dispose of acrylic paint water and of course I want to do that but I was interested if anyone knows or has tried reusing the leftover bits and what you did. Just trying to make use of as much paint as possible and be eco-conscious ?
    Thanks in advance friends!

    • Hello Sheila, thank you for your question and sorry about the late response. Here is one idea I mentioned in another comment. A painter I met here in Toronto and lived in Guelph Ontario had was creating artwork with concrete and was using the paint water instead of regular water to mix the concrete. I never did this myself but I think that’s a great idea. You can use this concrete to create lawn ornaments or planting pots.

    • Use the coloured waste water like George mentioned, for maybe some decorative concrete projects. If you have actual leftover paint bits, they’re now just small bits of coloured plastic 🙂 You can collect them and embed them in a project made with poured resin. They won’t dissolve in the resin, rather look like colourful floating bits.

  12. No… I would not recommend that HairBear,
    the dirty paint water can reach the water table thus contaminating fresh drinking water.
    It would be better to pour dirty water in the septic tank, because it is a sealed tank that should get pumped out by septic service provider every 2-5 years!
    Especially if you are a homeowner that does occasional painting projects around the house and not cleaning dirty brushes and rollers on a daily basis.


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