Cleaning Water Feature Rocks: The Complete Guide

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Water features can be a beautiful focal point of a home, garden, or pond. But in order for these decorative features to live up to their full potential, they need to be regularly cleaned and maintained.

All rock features with running water need to be cleaned regularly to avoid hard-water buildup, algae growth, and rust. The inside and outside parts of the feature both need care, and household cleaning products (such as baking soda) can be used to remove buildup on the exterior.

There are several different things that can cause damage to water feature rocks. For more information about water feature maintenance, preventative measures, and simple cleaning routines, read below!

Hard-water Buildup

When you’re looking at a water feature that’s covered in hard-water stains, slimy algae and can hardly function beneath all the crud, it’s easy to be intimidated.

So let’s all take a deep breath and get ready to tackle this problem! The first thing to be aware of is that water features need to be kept clean on the inside AND outside. The unsightly buildup on the rocks might be the thing that catches your attention, but your water feature needs deep cleaning as well as surface cleaning.

Some of the biggest enemies to a beautiful water feature are hard-water buildup and lime scales.

If your water features use groundwater with a high content of dissolved limestone and and chalk, you’ve probably already dealt with the crusty, light-colored deposits that build up around your fountain.

Hard water stains will bind strongly to the rock beneath, making it difficult to remove without damaging the base. Physically chipping or scraping it away can sometimes cause more harm than good, especially if you like the natural look of the rocks in your feature.

Luckily, there are a few easy ways to get rid of hard-water stains! Of course, there are commercial products available for this purpose. These are usually quite strong and effective, but they could also end up infiltrating the water supply.

If you have fish or plants connected to the water system, it might be better to avoid these strong chemicals.

There are home remedies available as well. These are easy to make and are quite effective at cleaning hard-water stains off of natural stones. The ingredients can be found among your everyday cleaners, or maybe even in your kitchen!

All you need for a home treatment is:

Stir together 1 cup of baking soda, 1/4 cup of vinegar, and 1 Tablespoon of dish soap. These should form a paste-like consistency. Depending on the number of rocks you want to clean, you can double or triple the batch for whatever size you need. Source

Spread the paste over the surface of each dampened rock and let it sit for 30 minutes. This waiting period gives the cleaner enough time to break down the hard-water deposits. Scrub the rocks with a cleaning brush, or even a toothbrush (just not the same one you use to brush your teeth!)

Once the rock has been scrubbed, rinse it with clean water and examine the hard-water stained area. If there is still some buildup there, you can repeat the process as many times as necessary.

Plant and Algae Growth

One of the perks of a water feature is connecting the outside world to your home. Whether it’s a swimming pool, fish pond, or fountain, any water feature can help us feel just a little closer to nature.

On the other hand, that means we also need to keep some natural forces in check! Lots of plants and algae can grow in freshwater systems, even ones as small as your water feature. As long as there’s water and the occasional bit of sun, you should expect to see algae from time to time.

Even if you want to have a bit of plant life in your fountain, you won’t want it to grow out of control and clog up the mechanisms. Rocks can often develop a film of algae when they’re submerged in water for a long time. This can make them slimy, discolored, smelly, and generally unappealing.

If you have fish connected to your water feature, algae can also be harmful to them by using up a lot of oxygen, clogging filters, and making the water murkier.

Luckily there are ways to keep plant growth under control. Depending on the size and composition of your water feature, some of these methods will work better than others.

1. Powerwash

If you’ve got a thick growth of algae on submerged rocks, power washing might be the way to go. You’ll want to drain the water feature and turn off the pumps.

You can either leave the rocks in the drained basin, or remove the affected rocks and place them on a flat surface. Pressure wash the top of the rocks and try to get between all the cracks. Refill the feature with clean water and skim any floating material off the top.

This method is quick and easy, but it’s not always the most effective in the long run. Sooner or later you’ll probably need to wash it again, so you’ll need to decide if this method is worth doing regularly.

2. Scrub

This method is similar to the first one, but more thorough and time-intensive. You’ll want to remove the affected rocks and scrub them with a firm brush. (Wire brushes can be used, but they may scratch or damage the rocks).

After they’ve all been scrubbed, you can rinse them with clean water and return them to their place in the water feature.

3. Boil and bleach

The boil and bleach method is probably the most effective at killing algae, but it could also cause problems if you have any fish or plants living in the water. It could also lighten the color of some rocks if you do it too often.

First, you’ll want to remove the affected rocks and soak them in boiling water for 20 minutes. After that, scrub the surface with a firm brush or toothbrush.

Next, prepare a solution of 95% water and 5% bleach. Soak each rock for 5 minutes, then remove them and rinse with both warm and cool water. Make sure they’ve been thoroughly rinsed because you don’t want any bleach in your water feature! Source

Finally, let the rocks sit in fresh water for a few more minutes then return them to their original position in the water feature.


Another factor that could be causing some changes in the rocks of your water feature is oxidation. Oxidation is the process by which water and oxygen breaks down specific minerals found in many rocks. Basically, oxidation causes rust!

This is a natural process and won’t usually cause damage to your water feature.

The main way this could become a problem is if the rocks are exposed to severe erosion conditions. For instance, a lot of high winds, freezing temperatures, and severe storms could eventually begin to break down the rocks, but that’s an inherent risk of building an outdoor feature in those conditions.

Most water features will be fairly well insulated from major instances of erosion, so this isn’t a big factor you should worry about.

If you notice some of your rocks turning a bit reddish, you might be seeing some new flecks of rust. This isn’t really something that needs to be cleaned, just something to be aware of.

If you prefer the color of the rocks you had before, you may need to replace them or just learn to appreciate the natural weathering process! Some people even enjoy the look of more weathered and oxidized rocks.

Clean Inside and Outside

Even if you get the outside rocks looking spotless, it won’t help much if there’s a bigger problem hidden under the surface.

Rust, plant growth, dead insects/animals, and a million other forms of debris can get trapped in the inner pipes and pumps of a water feature. On top of looking (and smelling) pretty bad, this can also slow down the water flow, contaminate the water supply, and break pieces of the machinery.

There are things that owners can do to prevent or minimize this damage, but at the end of the day, even the best water feature will need a bit of cleaning from time to time. Don’t be tempted to only address the outside buildup. The inside is probably even more important in the long run!

Luckily, most commercially-available water features are designed with these problems in mind. Most of them have built-in filters and screens that will catch any big particles. These should be easy to access, clean, and replace.

This is a great walkthrough video that can help you troubleshoot various parts of your water feature. There are a few different areas that could be giving you trouble, including the debris basket, filter mat, or even the pump itself.

Be sure to check out all of them just to be safe!

Preventative Measures

While everything needs a bit of cleaning from time to time, there are some steps that you can take to make the cleanings easier when they roll around. Some issues can even be prevented entirely!

First of all, make sure all your filters and screens are clean and clear. These exist to catch debris of all sizes, so it’s important to start with a clean slate and check up on them often.

If you have a regular schedule of checking, cleaning, and replacing filters, then larger clogs won’t be able to develop. Using a water skimmer on surface buildup can also help catch pieces of debris before they even make it to the filter area.

Next, check your water quality and level. Hard-water stains can happen more often if you’re using untreated groundwater. It may be an extra expense to use water softener, but it could also cut back on the number of cleanings in the future.

The water level is also very important to maintain. If the water is too low, your pump may not be able to function properly. This will make it easier for debris to build up, and can cause your pump to strain or break.

Generally speaking, the water level should be about 3/4 inch below the top of the skimmer mouth. During hot weather, you may need to add extra water to keep it at the right level to counteract evaporation.

Seasonal Care

Water features require different levels of care throughout the year. They may be pretty easy to maintain during one season, but difficult and challenging during another. Fall and spring are often high-maintenance seasons for those who own water features.

Spring is a major time when cleaning is important. When you’re getting ready to refill the water feature, you may notice debris and buildup that accumulated throughout the winter. This often necessitates a deep clean before the water feature can get going again.

Rinsing the feature with a hose or power washer can help clear out the gunk. I would suggest filling and draining the feature a few times as well, just to flush out the pipes and clear out material that may float to the surface. Talk about spring cleaning!

Fall is another important time of year, and with it comes the issue of falling leaves, decaying matter, and fluctuating temperatures that may freeze your fountain before you’re ready. You’ll need to be extra vigilant about checking the filters and debris catchers during this season.

It’s best to plan for winter early because fall can change to winter temperatures in the blink of an eye! Make an early plan about how you’ll use the water feature during the winter.

Some people like to keep it running to save the hassle of takedown and storage. Others like to use devices that will keep the water just above freezing temperature.

Otherwise, you’ll want to shut down your feature by removing your pump from the feature and storing it in an unfrozen bucket of water. Do one last cleaning of the filter, drain the water, and enjoy a winter without the need for maintenance!

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We always wanted a fountain of some kind at our house, but professional installation was just too pricey. So, we decided to make our own little fountain and after learning how, we thought we should share our experiences to help people in our same situation.

1 thought on “Cleaning Water Feature Rocks: The Complete Guide”

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