What Is An Overflow Bath Filler? Everything Explained

Were you at the spa wallowing in a herbal scented bath and marvelling at the sleek filler that poured hot water into your tub? There were no knobs or taps near it. What was that thing? It was likely an overflow bath filler.

In this post, I’ll explain what an overflow bath filler is, how to install one, its advantages as well as answer some common questions around the topic.

Let’s dive in!

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What Is An Overflow Bath Filler?

In a traditional bath, you have a separate fixture for the filler spout and the overflow drain. An overflow bath filler combines both functions into a single visible piece. The hot and cold taps may be positioned above it or elsewhere in the room. It removes the need for a separate tap spout as the water pours into the bath through the baths overflow.

How Do You Fit An Overflow Bath Filler?

Since you are eliminating the tub spout from your bath and shower configuration when installing an overflow bath filler, it is best to approach the project as part of a renovation or new bathroom. You need access under and behind the tub, to the bath drain, and to the water supply pipes.

1. Assemble the Parts of the Kit

An overflow bath filler kit contains a valve body, flexible tube for the overflow drain, PVC connections for the drain, pop-up waste, and overflow filler cover. You need to follow the directions to connect the flexible tube to the valve body and the pop-up waste.

Make sure to place the flexible washers inside the quick connections to the water supply. Also, use the appropriate nylon rings to create a seal between the downpipe and the pop-up waste unit.

You will need a spanner or two to tighten a few bolts into place. You don’t need any putty, glue, or additional parts besides what came in the box.

2. Install the Filler

Now that you have the filler connected to the drain, you need to pop the unit into place. You need to have access behind and under the bathtub.

Place the filler gasket around the hole cut in the side of the bath for the overflow filler.

Position the unit so that the valve pin comes through the hole from the backside of the tub and cover it with the filler shroud.

Use the provided nut to secure the shroud to the valve.

Finally, secure the overflow filler cover.

3. Attach the Overflow Drain

On the bottom of the bath, pop the drain gasket into place.

Press the drain assembly up underneath, creating a watertight seal between the pipe and the gasket.

Place the drain cover on top and secure it in place.

Adjust your pop-up waste to allow for slow or fast draining of your bath and snap into place.

When it is working properly, the closed pop-up waste will open the overflow pipe at the filler to prevent the tub from overflowing.

Don’t forget to connect the overflow drain to your regular bath drain!

4. Connect to Your Water Supply

Finally, you will use the quick-connect braided hose to connect the valve assembly to your hot and cold water supply.

Top Tips for a Stress-Free Installation

You can attempt installing an overflow bath filler in an existing bath if your bath uses panels to cover the side of the tub. By removing the panels, you gain access to the drain connection for the tub and to the wall behind the bath.

If you are eliminating the traditional filler for your bath taps, buy an escutcheon plate that will cover the now-empty hole on the side of the tub for a seamless finish.

Go Wireless!

You can replace your old-fashioned hot and cold water taps with an electronic control panel that can be accessed by your smartphone! Simply open the app and ask your bath to start filling. How cool is that?
Check out the Aqualisa Unity Q Smart concealed bath filler with overflow.

Bathtub with an Overflow Bath Filler installed

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Advantages Of An Overflow Bath Filler:

Why would you want to opt for an overflow bath filler instead of sticking with the traditional spout and taps? There are a few perks to going with this contemporary upgrade for your bathroom renovation.

Space Saving

If you have a smaller tub or are a taller person, bumping into the bath filler can be painful! When you install an overflow bath filler, you eliminate that extra piece of hardware hanging out in the bath. Should you have a tub with a wide lip, you have more room for shampoo bottles, loofahs, and soaps.

Minimalist & Modern Look

There is no doubt that these fillers look like they belong in a sci-fi flick or at least on a page of your favourite home improvement site. It gives your bath a less fussy appearance that works well with the minimalist designs flooding home decor sites. You can find a filler cover that matches traditional slipper tubs or a square or diamond that better supports the geometric floor and wall tiles. Your guests will think that they are at the spa!

Position Your Taps for Your Convenience

You will still need to turn on and off the water, but since you are going with the overflow filler, you can choose where to put your hot and cold taps. They do not have to be over your filler. Place them on the wall behind the tub or outside the enclosure, so you can set the temperature before you dip a toe in the water.

Perfect Temperature

With this filler, you can adjust the temperature of your bath while you are soaking! Did it get too cool? Turn on the hot water and set the warmth to circulate down into the bath while the cool surface water is directed down the drain. There is no need to empty the tub and change the heat level.


Don’t you love things that do two things instead of one? This is simply a smarter solution to the need to both fill up your bath and prevent a disaster when you walk away while it is filling.

How Much Does An Overflow Bath Filler Cost?

There are overflow fillers designed for every budget. Look for one that complements your budget-priced sanitaryware that starts at around £50. You can find ones finished out in bronze or gold that best reflect your luxury upgrades for about £300. Or go high-tech and wireless for around £400-500.

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Do I Need Taps With An Overflow Bath Filler?

Yes, you still need your hot and cold water taps or a digital smartvalve. However, you won’t need a bath spout. When you’re shopping for your finishes for the bathroom renovation, you may have to buy the taps separately from the overflow bath filler. So double-check what’s included in the kit.

Traditional bath taps with hot, cold, and filler are sold as a single unit or at least in the same box. You can select a mixer valve or a pair of old-fashioned taps and install them anywhere you like in the bathroom. You will run the connection from the taps to the filler behind the walls for a seamless appearance.

All taps are sold with universal connections, so you don’t need to worry about mixing and matching. You can buy a separate overflow filler cover that better matches the finish of the water taps on which you decided.

Are Overflow Bath Fillers Slow?

Some overflow bath fillers are slower than a traditional spout. It all has to do with the size of the supply hoses. If the valve on your filler is smaller than your old spout, it will take longer to top up the tub.

However, if you change out your 70-year-old taps for a set of new ones from the DIY store, you are likely to experience the same drop in water flow. Ultimately, you are looking at waiting an extra minute or two before sliding beneath the bubbles.

Final Thoughts…

There you have it! Everything you need to know about overflow bath fillers.

A space-saving, modern and minimalist look that gives a little wow factor and sense of luxury to any bathtub.

So, what do you think, will you go for an overflow bath filler in your new bathroom renovation?


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.