How to Add Water to a Pond: The 9 Do’s and Don’ts

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Photo 84835046 | © Zayacskz |

Whether you’re an experienced pond owner or someone who’s considering getting one, there’s always something new to learn. Adding water to the pond is debatably the most influential, dangerous part of the process. Fortunately, you’re in the right place to learn everything you need to know.

To add water to a pond, you need to choose a source, such as the tap, hose, rainwater, or trickling in from another natural body of water. Next, choose if you’re going to treat the water with a dechlor or water conditioner to make it safe for the pond. Finally, add about 10% of new water every week.

This post will also teach you everything about adding water to a pond, including:

  • All of the do’s and don’ts for adding new water
  • How often you need to add it
  • Different sources to choose from
  • How to treat the water before putting it into your pond
  • Various suggestions to make it easier and safer

Can You Add Tap Water to a Pond?

Never add tap water straight into your pond. Even if it doesn’t have fish, the chlorine found in tap water can prove fatal for any lifeform, including plants. If you want to add tap water out of pure convenience, you must treat it properly before adding it to your pond.

Try this quick guide to purify your tap water:

  1. Measure the chlorine content in the water. Try using Qguai Aquarium Test Strips (link to Amazon). They show pH, chlorine, salinity, copper, hardness, and more.
  2. Let the water sit in a 5-gallon bucket (or a large, clean garbage can) for at least 24 hours.
  3. Treat it with a water conditioner or dechlor solution. For more information about these two treatments, read on.

Can You Put Hose Water in a Pond?

Photo 126736497 | © Tobias Lindner |

Much like tap water, it’s highly unsafe to add hose water directly into the pond. Not only does it have chlorine, but your hose likely has several types of algae or bacteria. These substances can be horrible for the plants and fish in the pond.

Let the water sit in a separate container until the algae settle to the bottom. Even if it looks clean at first, a 24-hour wait will show you everything that falls to the bottom of the bucket or can. Treat it with the same suggested solutions from above.

Using Rainwater to Fill a Pond

As Pond Talk suggests, the best way to use rainwater in a pond is to run it through a filter beforehand. Use charcoal or even a simple, fine mesh net to remove impurities. If you’re worried about the various chemicals in the water, consider using a test kit, as mentioned in the tap water section.

Using rainwater to fill a pond is one of the most efficient ways to do so. Many experts highly recommend it since it’s a free, mostly-pure form of water.

Trickle Water From Another Natural Source

You could also add water from another natural source, such as a lake, river, stream, or another local pond. Always test the water with a test kit before you use any outside source of water. Also, it’s good to research the different types of algae or chemicals that might harm the plants and fish living in your pond before you start trickling it through.

Figuring out your water source is only the first step of the process. You also need to know how to treat it, how to control it, and how often you need to add more water. Follow the steps below for more details.

Consider Using Dechlor

Removing chlorine from water that you’re about to add to a pond is essential to your fish and plants’ lives. Use Total Pond Chlorine Remover Plus (link to Amazon) to quickly remove all traces of chlorine from tap water and hose water. A single bottle of this high-end solution provides enough dechlorinating liquid to treat over 1,900 gallons of pond water.

It’s important to remember that you should treat the water before it’s added. Never dump a bottle of dechlorinator directly into a pond. Use a 5-gallon bucket or another clean, large container to treat the water, then pour it into the pond.

Consider Using Water Conditioner

If you want to take it a step further, you could try to use a water conditioner. Much like a dechlor solution, the water conditioner treats the water to remove impurities. However, it takes out more than just chlorine.

For example, Seachem Pond Prime Water Conditioner (link to Amazon) also removes toxins, ammonia, and nitrates found in your pond. It also takes out chloramines, which are often neglected in most dechlor treatments. This conditioner even stimulates the growth of healthy slime and algae to stimulate the ecosystem of the pond.

Always Add a Shutoff Valve

If you’re filling your pond with a hose (of treated water), copper, or PVC pipes, you should use a shutoff valve. One hundred gallons might seem like a lot, but never assume that you can walk away and time it perfectly to manually shut off the water source. Koi Health points out that failure to use a valve can result in excess water or chlorine contamination.

Another reason to add a shutoff valve is that it can save you more money. If you want away and the pond floods, you’re wasting water. Shutoff valves are cheap and critical to the livelihood of your pond. They only take a few minutes to install, but it can make a world of difference.

Add Water Weekly

Adding water to your pond has numerous benefits. For example, The Pond Guy notes that a few gallons can change stabilize the pH, fight unhealthy foam, and clear up your fishes’ eyesight. It also removes nitrates, phosphates, urine, and feces from your fish.

It’s recommended that you change between 10% to 20% of the water every week. If you live in a warm, dry climate that evaporates most of the water, you’ll definitely have to be at the high end of the scale. Those who live in humid, cold environments might even add as low as 5% fresh, treated water per week.

Perform Trial Runs

Finally, you should try a few trial runs before making any major changes. Don’t jump right into changing 25% of the pond water if it’s not absolutely necessary. Instead, consider adding 10 gallons to a 500-gallon pond. Treat the water beforehand and see how the fish and plants react. If everything goes smoothly, you can start making it a routine.

It might seem like a lot of work at first, but once you get the hang of it, adding water to your fish pond is easy and quite enjoyable. Knowing that the plants and fish in your pond are getting the nutrients they need is enough of a reward to continue following the recommended guidelines.


Whether you’re using hose water, rainwater, or another water source for your pond, testing and treating are the best courses of action. The goal is to ensure that the water stays clear and that your plants and fish are getting everything they need to survive and thrive.

Here’s a quick breakdown of the article:

  • Change between 10% to 20% of the water every week (unless it doesn’t require changing).
  • Water from hoses and the tap should be treated to remove chlorine and chloramines.
  • Always use a test kit to check the pH, hardness, copper, iron, chlorine, and other properties.
  • Use dechlor or water conditioner to treat the pond water.
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