Can You Add Water To A Toilet Tank?

At some point, you might find yourself in a situation where the toilet tank doesn’t have enough water to flush — usually because something’s gone wrong or the water’s been shut off unexpectedly. In this unfortunate situation, can you add water to the toilet tank to fill it up?

You can add water to a toilet tank to fill it up. When the water is shut off, toilets usually have another flush in them — but if you need more, you can manually add water. Look for a water line to be sure you’re adding the right amount, and expect to need to top it up after each flush.

Let’s take a closer look at how to add water to a toilet tank successfully, as well as some other things you might need to keep in mind.

How to Add Water to a Toilet Tank

Simple bathroom interior with new toilet bowl

First, you should remove the lid of the toilet tank and set it aside. If you’re lucky, there will be a line inside that shows you where the water should sit and you’ll be able to quickly see if there isn’t enough water.

If your toilet doesn’t have this line, the water should usually sit a couple of inches below the overflow valve (at least make sure there’s enough room so that they aren’t touching). You may also want to research your specific toilet before putting water in.

Once you’ve done this, make sure that the water is still turned off before you add more to the tank.

If you do have water going to the toilet and the fill level is just off, you can adjust this using the fill valve inside of the tank. You’ll find it on the left. You may have to turn it or adjust a clip, depending on the kind of toilet you have, but moving it one way will usually raise the water level and the other will lower it.

How Much Water Does a Toilet Tank Hold?

Modern toilets will usually hold between five and seven gallons of water, but older toilets could be as low as three and a half per flush.

It really depends on your toilet and when it was made, but the only solid way to tell is the fill line.

Finding the Fill Line

Usually, the fill line will be etched inside of the toilet tank and you can see it. If you can’t, run your fingers along the inside and you might be able to find it that way.

Some toilets don’t have a fill line, so it’s entirely possible yours doesn’t — in which case, you should determine the appropriate level using the overflow valve.

How to Adjust the Water

If you have water coming to the toilet, you can use the overflow valve to adjust it. However, if you don’t, you’ll have to pour water in manually. You’ll have to do it for every flush, so carefully measure how much water you need before you go ahead and pour it. 

Using Water to Flush a Toilet

Pour the water into the tank up to the fill line and then flush and the waste should go down. If you don’t pour the right amount of water in, you might discover that the waste doesn’t go away.

You can also pour the water directly into the bowl to flush it, although you still need to measure it out and make sure there’s enough force for it to go down. Pouring it gently into the bowl will just result in the bowl filling up, so make sure you do it in one great drop. 

Other Things to Keep in Mind

a man s hand in a glove opens the lid of the toilet flush tank

It’s always a great idea to prepare in advance for a water shortage, especially if you know a drought is coming or there’s planned maintenance. Keep plenty of water stored not just for drinking, but for flushing the toilet as well. 

You should also remember that these methods will vary greatly depending on what kind of toilet you have. If you’re unsure or can’t find the fill line, proceed with caution to ensure you don’t overload the system or do any damage to the toilet.

It’s also a good idea to take a note of how much water it takes to bring the tank to the fill line, as you can then use that in the future by pouring it directly into the bowl. There’s no need to keep removing the lid every time there’s a shortage!