How To Make Tap Water Safe For Ponds | Aquascape Addiction

How To Make Tap Water Safe For Ponds

This is a detailed guide on how to make tap water safe for ponds, what you need to lookout for and how to remove chlorine to get the right parameters.

How To Make Tap Water Safe For Ponds

If you have any kind of indoor or outdoor pond for your fish, you obviously want to provide them with the best home possible. One of the most important things to consider with ponds is the water. After all, fish cannot live outside of water, so this is crucial no doubt. However, simply having water in the pond is not good enough.

The water needs to be the right water, treated the right way, with the right parameters. You can’t just go and pour a bunch of water from your tap or hose into a pond for fish. That will not end well by any means.

Tap water just is not safe for ponds, unless you treat it of course. The problem here is the chlorine. How to make tap water safe for ponds is what we are here to talk about right now. There are ways to remove chlorine and its derivatives or manmade compounds from the water, so fear not.

The Problem With Tap Water – Chlorine

The main problem that tap water brings to the pond is chlorine. All tap water in our world, in developed countries anyway, is treated with various chemicals including chlorine. Chlorine is used to disinfect water, kill bacteria and parasites, to remove bad odors, and to make it consumable for humans.

Yes, chlorine might be fine to consume in small amounts (or so city officials claim), but it is definitely not safe for fish or for plants in a pond. Moreover, chloramine is often being used to treat tap water as well. While both chlorine and chloramine are not great for humans, they are deadly for fish.

Chlorine can actually evaporate into the air, which means that it is not all that hard to deal with on its own. However, many places are now using chloramine, which is a mix between ammonia and chlorine. This stuff does not evaporate into the air, making the problem just that much worse.

Why Is Chlorine Dangerous To Ponds & Fish

As you have probably gathered by now, chlorine is extremely dangerous to fish and pond plants alike. First and foremost, chlorine kills fish outright. There is no question about that. Chlorine damages a fish’s gills, scales, and breathing tissue. It literally burns them from the outside. Also, as it passed through their gills and digestive system, it also burns them from the inside out.

Chlorine can kill fish really fast. Moreover, chlorine also kills off all of the good bacteria in the pond. Ponds need to have beneficial bacteria that kill ammonia and nitrites. Without these bacteria, which are now dead because of chlorine, ammonia and nitrite buildups will kill the fish.

Now, add to the fact that most water uses chloramine for disinfecting, which is the mix of ammonia and chlorine, and you have a deadly cocktail that will kill your fish without question.

Chlorine vs Chloramine

Just to clarify, chlorine is terrible for fish, but chloramine is even worse. We know that chlorine kills fish in more ways than one. Well, the addition of ammonia to chlorine, which creates chloramine, causes even more problems. Water providers use chloramine to save money because it doesn’t evaporate out of water like chlorine does.

For people who have aquariums and ponds, this is a really big problem. This means that many solutions which would normally work to dechlorinate water don’t work for chloramine.

One of the first things that you want to do is to contact your local water company to see if they use chlorine or chloramine. You definitely don’t want to treat the tap water for chlorine, only to find out that chloramine is what has been used.

Measuring Chlorine In Water & Ponds

In all reality, the water you put in the pond should have absolutely no chlorine in it. When it comes to both chlorine and chloramine, the ideal level is 0.00 parts per million, or in other words, none at all. Both of these substances or compounds have no place in an aquarium or pond, they have no benefits whatsoever, and the only thing they will do is kill your fish.

It might be impossible to remove all chlorine and chloramine from tap water, but you should aim for levels as low as possible. 0.01 parts per million is an acceptable level, but even that is already pushing it.

Any more than that and you are asking for trouble. You can use an ammonia detection kit to measure your water for ammonia. If there is ammonia present, there is most likely chloramine in the water. There are special chlorine testing kits and electronic testing tools which are well worth getting (we have reviewed some good options over here).

How To Remove Chlorine From Water To Make It Safe For Fish

There are several ways that you can remove chlorine from the water to make it safe for pond fish. Keep in mind that not all of these methods work for chloramine, for the reasons we have discussed above. Some of the below methods will work for chloramine, but not all, so we will be sure to clarify.

Letting Water Stand

Ok, so this first method, to be crystal clear, only works for chlorine. You can let tap water stand for about 48 hours and the chlorine will simply evaporate out of it and into the atmosphere. Once again, chloramine does not dissipate into the atmosphere, so this method will not work for water that contains chloramine.

Water Conditioners

Probably the best and the most common option to go with is a water conditioner. You can find these at any fish keeping store. These conditioners work to remove chlorine, chloramine, and other poisonous and unwanted substances from the water.

Always be sure to read the directions though, because not quite all water conditioners out there can handle chloramine. Also read the directions in terms of dosing. Too much of this stuff is not good either. On that same note, some water conditioners need to be used before the water is added to the pond, while some can be added directly into the pond.

Activated Carbon Charcoal Filters

We are not going to get into the science of things here, but the fact is that activated carbon charcoal filters are great for removing chlorine, chloramine, and a ton of other substances from the water. This stuff can remove pollutants, pesticides, medicines, perfumes, chlorine, chloramine, and tannins from water.

These are all things which should not be in pond water for fish. It does work really well on its own, but is best used with a water conditioner or water that has already been treated. While it is a great measure to get rid of chlorine and chloramine, it should be used in conjunction with other methods for optimal results.

A Dechlorinator

Once again, we don’t want to get too technical here, but dechlorinators are like specialized aquarium filters dedicated to removing chlorine and chloramine from the water (we have reviewed some good ones here).

It’s pretty much a special aquarium filter with media designed to fight this problem. It is a good option to go with if you have a big pond with lots of fish and perform water changes fairly often.


No matter what the case, always remember that you need to treat tap water for chlorine or chloramine before adding it into a fish pond. The above methods on their own work well, but in conjunction with one another they work the best.