How To Clean River Rocks: A Beginner’s Guide

Let’s talk practical strategies for cleaning the river rock you’ve got at your house.

In this article, we’ll cover strategies for cleaning small amounts of rock you’ve picked up (like rockhounding for pretties), larger amounts that haven’t found a home just yet, and rock that has been in your yard for a while.

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How To Clean River Rocks (Small Amounts, A Bucket Or Less)

What you need to do to clean your landscaping river rocks really depends on what state they are in, where those rocks have come from, and how much rock you have to clean.

If you are bringing in river rock straight from a natural location (like you took a bucket out with you on a hike), that river rock is going to be really dirty, even if it looked pretty in the water.

The rock is probably coated with silt and various forms of organic matter (like algae), and that gunk is going to be found in all of the nooks and crannies of the pieces.

If you have a small amount of rock, here’s what we recommend:

First, put the rock in a bucket and put in enough clean water (from the hose, not the river) to cover them. Allow them to soak for 30-60 minutes. Stir and swirl the rocks to loosen any organic material. Dump the water, and repeat if the rocks still don’t look or feel clean.

If you wash the rocks 2-3 times in the bucket after soaking and they are still dirty or covered with some organic matter, try spraying them (in the bucket) with the hose. Spray, stir, drain the water, and repeat.

If stirring isn’t enough, grab a scrub brush and scrub and stir, rinse and repeat.

The reason we recommend that you keep them in the bucket when you spray them with a jet of water or stir/scrub them is that the small river rocks weigh very little and are easily thrown around by any kind of force. The last thing you want is all of your carefully collected rocks rolling all over your yard.

If you find that soaking and spraying your rocks doesn’t do the job completely, you could try adding bleach or vinegar to your water bath/soaking bucket. Just don’t add them to the rocks at the same time, as you’ll create a dangerous gas.

If you do utilize vinegar or bleach, make sure to do a few soaks of clean water after draining the bleach solution away to make sure that bleach is completely washed out.

How To Clean River Rocks (Larger Amounts)

When you have more rocks to clean, you will have to be a bit more creative.

The issue with rock rock is that the pieces tend to be pretty small, and also various shapes and sizes. It is not feasible to scrub each tiny rock by hand. If you try to take a scrub brush to them en masse, they roll away and it’s tough to get at them effectively.

This is when a metal screen mesh can come in really handy. You can knock together some 2x2s or 2x4s into a square, and staple the mesh onto the square.

Then put your rocks on a flat surface (like the driveway), put the mesh box over the top, and then spray away through the mesh screen.

Power washing can clean up your rocks quickly, but if you turn up the pressure too much, the rocks can bounce around, chip, crack, or even break apart.

How To Clean River Rivers (Fish/Animal Tanks)

In general, we don’t recommend that you put river rocks in your fish tank or animal tank directly from the river or outdoors into your tank. The rocks can change the hardness of the water or the pH. They also often come with contaminants that could harm your critters.

River rocks might look solid and smooth, but they are full or holes and cracks, in many cases too small for us to see. There’s water in those rocks, even if they look dry. There’s organic matter on those rocks, even if they look clean.

And in many cases, there are organisms living in or on the rocks that you can’t see.

If you are planning on putting rocks you’ve collected from the outdoors into your tank, you need to clean them really well:

  • soak them in clean water
  • swish, stir, rinse, and scrub the rocks to loosen material
  • rinse
  • soak them again in clean water
  • rinse
  • soak again, but with vinegar or bleach added to the mix
  • swish, stir, rinse, and scrub
  • Soak again in tap water
  • place rocks in a big pot, and boil for 30-45 minutes (we like to do this outside, though the rocks probably won’t explode like they would in a fire, it is still nice to not have that anxiety), some people like to put them in the dishwasher
  • Rinse rocks
  • soak again in clean water
  • Allow rocks to dry completely over a period of several days

How To Clean River Rocks (Already Placed In Your Yard)

The challenge comes when your river rocks are already in your yard.

Over time, organic material accumulates on or around them. They start to look dull and dirty, or they become buried in the decaying debris (leaves, needles, etc).

When you have a lot of rocks, it is not as easy as getting our your brush and bucket.

The first thing we would do when trying to clean up river rocks in landscaping is to first go through and remove as much of the organic matter that has been mixed into your rocks that doesn’t belong there.

Pull weeds, sweep out dead leaves, dig out mossy spots. If the rock is large enough, try using a blower to push out pesky needles and other small materials.

If there is dirt peeking through that is mixed in with your rocks because it has been a long time since the rocks had been cleaned, consider scooping out the rock and putting it on a mesh screen (like a strainer). This should help get a lot of that particulate matter that is hard to grab with your fingers.

This could be a good time to consider putting a barrier in underneath your landscaping river rock if you don’t already have one. Yard fabric is a good choice, because it lets moisture through and water won’t collect and pool.

People also use black plastic, burlap, or even cardboard.

Once you have the organic material pulled and removed, we take a hose (not the power washer) and spray the rocks where they are in place. Spray, then use the broom and swish and brush them.

Then spray again. And swish and brush. This should do a lot to remove most of the grime and dirt that accumulates on the rocks over time.

If you don’t think this is enough, or the rocks don’t look clean enough, consider dipping your broom in a soapy water solution before swishing and scrubbing.

In choosing a soap, remember that the soapy water will run out into the soil below, and could impact the nearby greenery. Try something biodegradable so it will be less harmful for the environment.

If the soap isn’t working well, you could spray the rocks directly with the soapy water before scrubbing with a broom, or even employ a smaller brush to get at the rocks more directly.

Some people like to incorporate bleach or vinegar into the cleaning process, but generally we don’t like to use it. The runoff from the bleach if you use too much can kill other nearby grass or plants in the yard.

If spraying and scrubbing (in place) isn’t working, you could try busting out the power washer. In general, this only works at lower pressure and with larger rocks.

You could also scoop the rocks out into the mesh screen strainer we talked about earlier, to power spray or to scrub by hand with a brush.

If the rocks are particularly dirty or covered in algae, you can soak them in a bucket or wheelbarrow in water or a bleach/water mixture.

Ultimately, a bed of river rocks in the yard will require that you pull them out to strain out the accumulated organic matter that works its way down to the barrier layer. It decays into a really nice bed for weeds to grow in.

And if the rocks are really buried in the dirt, it might just be less work to dig out the rocks (and the dirt), put in a new ground cover layer, and bring in new/clean rock to replace what was removed.

Wrap Up

River rocks are really beautiful, especially if you make the effort to get them cleaned up before you use them.

If you want to go the extra mile, you can even add products to them to make the river rocks look wet in the yard, like they do when you found them in the river.