Why Is Bathtub Overflow Drains So Low?(Complete Guide)

Bathtub Overflow Drains So Low

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Why Is Bathtub Overflow Drains So Low?

The bathtub overflow drain is so low because Bathtubs have a tub spout to drain excess water.

Bathtub overflow drains are specifically designed so that the bathtub will not overfill with water.

The low position of the overflow is necessary because you need some space between the top of the overflowing water and the bottom of the spout for air bubbles to form.

The bathtub’s overflow drain is usually placed about an inch above where you would turn the faucet off if it weren’t present.

This prevents water from rising above that point, but there needs to be enough room below the drain for it to work as expected.

So by default, all bathtub overflow drains are at this height or lower.

This varies slightly depending on what region you’re in, but several factors drive this;

including the size of the overflow pipe, the height of the tub spout, and how much you’re willing to pay for your new bathtub.

Does A Bathtub Require An Overflow Drain?

An overflow drain is a plumbing fixture that prevents sewage from backing up and overflowing into your home.

You will find the drain installed in the lowest part of the house, usually under a sink or toilet.

It works by collecting any excess water to flow out through pipes to an external drainage system.

This means you won’t have to worry about sewage coming back up into your home.

The overflow drain also keeps sewage from damaging floors and walls, which could be a costly repair for homeowners with septic systems that are not well maintained.

No. Bathtubs do not require an overflow drain.

This is because a bathtub needs a certain amount of water in it at all times so that the bather does not burn themselves on the hot surfaces.

Usually, a bathtub has a round overflow drain near the back edge of the tub at about one-third from the top of the tub.

This small hole is little more than an extended drain opening.

The inside diameter of this hole should be a bit larger than the thickness of any part of your shower head’s pipe that you wish to connect to “it.”

If your shower head pipe has a threaded end, make sure you can screw it into this overflow drain without having to force it or use tools.

If you cannot screw in your shower head using any tools, then you might need to use a larger diameter pipe or cut that section of thread off.

You can also buy adapters explicitly designed to connect the shower heads to standard plumbing size pipes.

A bathtub must have some way to drain it when there’s too much water, i.e.,

When someone is taking a shower, they leave the faucet on for too long without detection by anyone in the house.

A bathtub does not need an overflow drain because if enough water accumulates in it for there to be any concern about an injury.

Then opening one faucet should stop this from happening because water will begin draining through the existing faucet(s) until no more excess water accumulates inside the bathtub.

How Do You Bypass A Bathtub Overflow?

You bypass a bathtub overflow by turning the valve until it’s parallel with the water pipe.

You need to block this position by sliding a key or metal rod in so that you can turn it back if needed.

This will allow the bathtub to continue filling while turning off and protecting your home from flooding.

You also may turn the knob clockwise to shut off the water completely.

You can remove your key or metal rod to allow the tub to fill again once you have inspected the damage and are ready for more water.

This method is not recommended if you try to fix an ongoing problem with a bathtub overflow every time you want to use it, rather than during an emergency.

It’s best in this case to call a plumber. If your faucet still runs after turning it off, this could be due to mineral deposits inside called “scale,”

Which prevent water from running through all the pipes behind them. For minor cases like this, you will need to soak the affected areas in vinegar.

For more serious problems, you may have to call a plumber.

After several tries, turn off the water valve at the bottom of your water heater and drain all hot water from it if this doesn’t work. This will fix most low-flow issues.

Otherwise, turn off the main flow of water coming into your home, so there is no chance of flooding while trying to repair your bathtub overflow.

Can You Remove A Bathtub Overflow Drain?

No. It’s not possible to remove a bathtub overflow drain.

The purpose of the drain is that you can use the tub as an extra water source in case there isn’t enough hot water or if someone needs it for special health reasons, etc.

If you do not need extra water sources and would like to disable your overflow drain, here are some ways that you can do that:

Non-Permanent Solutions

Change the order of your plumbing – Put your faucet before or after your overflow drain. If it goes after, connect the piping so that there’s no way for any water to enter it.

This will prevent debris from entering your overflow drain and clogging it up completely, at least until you fix this problem for good.

Block overflow drainpipe – If you need access to the plumbing for whatever reason, block off the overflow drain by putting a stopper in it.

This will prevent water from overflowing and spilling out of the tub. However, this is not a lasting resolution because it will still function as intended if your brain works again.

Permanently disable the overflow drain – To solve this problem for good, turn off the supply valve that lets water into your overflow drain.

You’ll know which one it is because there’s usually only one other pipe that goes into your bathtub aside from your faucet piping.

Turn off its supply valve and seal over any holes with caulk so that there’s no way water could get through without you loosening up the caulk.

Can You Replace The Overflow In A Bathtub?

Yes, you can replace the overflow in a bathtub. To replace it, you need to remove all the pipes and components under the tub.

A bathtub’s overflow keeps water from flowing out of it when it’s filled above a certain point.

When filling a bathtub beyond this point would cause water to flow over the side;

An overflow pipe stops this from happening by diverting some of the incoming water into a holding tank where there’s no danger of it spilling onto the floor.

The purpose of an overflow pipe is often lost on many homeowners;

And they might start taking them for granted until one leaks or develops serious problems with clogs and corrosion, that is.

If that happens, then chances are it’s time to replace the tub’s overflow. Replacing an overflow is pretty simple;

However, ensure that you have drained all the water from your bathtub before you try doing it yourself or call a plumber.

Disconnecting and reconnecting drain pipes can be extremely messy.

If any of the old bolts attaching the overflow to the rest of your plumbing get rusted or corroded.

Then replacing them with new ones will ensure that everything stays firmly put once you’re done.

However, if they seem in good condition, simply disconnecting them might do the trick just fine.

Does The Tub Overflow Face Up Or Down?

The truth is, it depends. It should face down on a full bathtub, but some tubs have overflows that allow water to drain from the top of the overflow.

Meaning it would be better if the overflow faced up instead.

The overflow prevents a tub from overflowing or spilling out by channeling the excess water out of the tub through its open end.

There are two main types of overflows: “recessed” and “rim” overflows.

In both cases, at least one flat surface called a weir ensures no water can escape except through the overflow itself.

Rim style overflows typically have their weirs set below the rim level to prevent splashing when they are in use.

Can I Use A Drain With Overflow In A Sink Without Overflow?

Yes, you can use a drain with overflow in a sink without overflow. Drain with overflow is a drain system that allows for continuous flow while preventing spillage from the sink.

A drain without overflow will not allow a sink to continue draining without overflowing. You can combine the two systems into one unit or exist separately in the same sink.

To have both a drain with overflow and a drain without overflow installed in the same sink,

You must have enough space between them for water from one side to get to the other side before it spills over onto the countertop below.

In most cases, this means that you would need at least two inches of distance between them.

You cannot always guarantee this without testing because every installation depends on your sink’s size and the type of pipes used.

If you want a drain with overflow and a drain without overflow in the same sink, speak to an experienced plumber about the best method for connecting them.

One option would be to combine them into one larger-than-normal pipe system with two individual drains underneath the sink.

This installation would allow water from each side to flow into that main drainpipe before spillage onto the countertop below.

Another option would be to install an air gap at least two inches away from either side of your double-drain system.

An air gap is rarely recommended because it does not permit continuous draining, but there are situations where it may be ideal for your needs, like having both types of drains.

Where Does Sinks Overflow Go?

It goes to the sewage line. It’s usually a trap on the main sewage line, under the sink.

It goes all over to sewage plants, and they can technically filter it out and make water safe for human use again.

Sink overflows dump into the sewer line, and sewage is thoroughly treated to remove harmful materials.

You could reuse the remaining water sometimes for irrigation, which, when done correctly, is safe to use on food crops. 

Can I Pour Bleach Down The Drain?

No. Never pour bleach down the drain. Bleach contains chlorine, which reacts with organic materials in septic tanks or sewer systems.

This reaction can produce poisonous gases that kill fish and other wildlife. Other excellent alternatives are to remove stains from your laundry, bathtub, sink, or toilet bowl.

Does Bleach Damage Toilet Bowls?

Yes, bleach can damage toilet bowls. Bleach is corrosive, and using it to clean your toilet bowl can cause irreparable damage.

Bleach has an active ingredient of chlorine dioxide.

This element is very corrosive to most metals, and the acidity level depends on which percentage of water and bleach you use in any mixture.

A 5% solution will be less acidic than a 10% but could pose a significant risk for developing pit marks if left on too long or not rinsed entirely off.

The high levels of bleach found in bathrooms can exacerbate the problem and pitting corrosion on the bowl surface.

To avoid these problems, it’s better to use a toilet-specific cleaner diluted according to instructions.

Even then, only clean the toilet bowl once every other month.

To remove pitting corrosion or limescale build-up, one may need to apply some elbow grease with steel wool or use an abrasive paste and a soft sponge.


The overflow drain in a bathtub helps prevent water from pouring over the tub’s rim when it fills too high.

This way, you can fill your bath without worrying about flooding out into your bathroom or house.

If an overflow pipe was not installed in your bathtub during construction, then there are some steps you can take to bypass this problem and install one yourself.

You will need to know how deep the hole in the floor is so that you buy an appropriately sized pipe for installation.

Once you have these materials together, find someone with plumbing work experience. They should be able to handle any overflow drainage needs that arise at their location.


Hi! I' am Tom. I was a manager in one of the biggest stores for over 10 Years, am also an SEO by night. I don't like to call myself a blogger; they are very analytical, do email marketing, and know all SEO stuff. I faced many questions from customers about different products, and there was hardly any help on the internet. After learning all the things about these products as a manager the hard way, I decided to start a blog and help other people.

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