Is it safe for cats to drink pond water?

Here is a neat test: would you go over to a pond that your cat might drink from, scoop up some water from it with a glass and drink it? If your answer is no (and I expect that it is) you can’t allow your cat to drink from it either. This test is 99% accurate but it does not take into account the possibility that lily pollen or any other part of a lily may be in the water. Many lily species are very toxic to domestic cats. The problem is pathogens and bugs in the water. You don’t know what is in there. Although cats will like to drink from ponds especially if it is filled with rainwater which does not contain purification chemicals which cats can detect.

Ginger cat drinking from pond
Ginger cat drinking from pond. Photo: Warren Photographic. Published her with his express permission.
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

Pond treatments

The answer to the question in the title must depend on whether the water has been treated by the homeowner or anyone else and do you know if it is being treated? There are various treatments for ponds in back gardens (backyards). Some of them keep away algae and others, for example, are pH buffers which ensures that the pH of the water is balanced because this is important for the health and welfare of the fish who live in the pond.

I don’t know what is in these treatments. They are chemicals. They may be entirely safe but you’ll need to discover the eact constituents components before you allow your cat to drink from a pond. Even without chemical treatments there may be some hazards because the water may become stagnant and unhealthy. This would concern me if I had a pond in my back garden.

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There is a problem and it is this. You might realise that domestic cats have a propensity to drink water from dirty puddles and any other source of rainwater that might be lying around outside (if they are allowed outside, of course). It is said that this is because rainwater is relatively pure and free of chemicals compared to tapwater which will contain some type of treatment such as chlorine or fluoride. According to the NHS in the UK, fluoride is naturally occurring in water but tapwater is chlorinated. This won’t apply to many countries but it certainly applies to many developed countries. Cats drink tap water, of course, but they notice the smell and the taste of the chlorine which can make them less eager to drink it compared to rainwater. Pond water is partly rainwater and therefore they may be encouraged to drink from a pond which takes me neatly back to the original problems mentioned above.

Mains water supplies the pond

The answer to the question in the title is based upon commonsense and it doesn’t need to be spelled-out. You just have to make sure that the pond water in your pond is potable (safe to drink; drinkable). A pond may be fed with freshwater from the mains i.e. it has the same source as tapwater inside the home. This water may fall down rocky waterfalls as a feature of the pond. The water in the pond may be recycled with a pump and also filtered. The walls of the pound may be made out of a safe material. Under these circumstances you would think that your cat could drink from this pond. My test in the opening paragraph still applies, however.

Fish, aquatic life, algae and plants including lilies

There is also the matter of the fish or any other aquatic life in the pond. Are they safe from your cat? They probably are. I just remembered another possible source of toxins for your cat if he or she drinks from a pond. The plants in and around the pond may be toxic to cats.

In fact, blue-green algae is also potentially harmful. It is composed of bacteria which resembles algae when it blooms. Blue-algae is cyan in colour and is created by cyanobacteria which contains a host of harmful toxins. I don’t know of any particular species of plant or tree which might be toxic to a cat should some of the leaves, pollen or foliage end up in pond water except for lilies which can be extremely toxic. I suspect this will usually not be a problem but it might be and you do not want to take a risk. You can get fences for ponds which may reassure some cat owners. I’m not sure of the objective of these fences but they may help stop a cat casually drinking from a pond if it concerns you.

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