Does a Bathtub Have to Have an Overflow Drain?

You’ve just started running a hot bath when the doorbell rings. Ten minutes later, you rush back upstairs to find water lapping at the overflow drain. The good news is, that’s as far as the water can go, thanks to that little drain below the taps.

A bathtub does not have to have an overflow drain but a bathroom must have a mechanism to prevent flooding. Having a floor drain can be a practical alternative but insurance and building code considerations should be factored into your decision.

The following article will look at what overflow drains are, what they’re for, and if they can overflow. I will also show you how overflow drains work, what to do if your overflow drain is missing, and how to install an overflow drain cover. 

What is an Overflow Drain?

An overflow drain functions as a secondary drain on your bathtub or sink, but the primary drain is the plughole at the bottom.

Overflow drains are circular holes situated just below the taps. Some have covers or windows you can open and shut, and some have covers that block the drain completely. 

Your overflow drain could be metal, rubber, or plastic, although they usually match the taps. 

What does an overflow drain do?

The purpose of an overflow drain is to prevent flooding (source). We’ve all started filling the tub and got distracted, only to find out later that the bathtub is dangerously full. Fortunately, this situation is precisely what an overflow drain was created for.

An overflow drain will siphon off the excess water, so your bath water can’t reach any further up the bathtub than the overflow drain. This prevents water from reaching the top of the bath, or worse, flooding over it. 

How does an overflow drain work?

Your overflow drain acts as a plughole for water that would otherwise flood the room. It’s found near the top of the bathtub, where it can redirect water safely into the drain.

Without an overflow drain, the excess water would simply flow over the sides of your bath and onto your bathroom floor instead.

Overflow drains for bathtubs come in two types:

1. Traditional overflow: the overflow drain is installed in the side of the bath, collects excess water, and sends it down the drain.

2. Integral overflow: found beneath the taps, an integral overflow drain siphons the water down the drain from within the bathtub.

Can an overflow drain, overflow?

If your overflow drain is completely blocked, for instance, with a cover, your bath could overflow. The drain itself, however, can be susceptible to leaks, especially if it’s old.

How do I tell if my overflow drain is leaking?

It’s usually easy to find the source of a leak, just run the bath and watch out for water appearing on the floor. Check your faucets, tub spout, and showerhead to rule out leaks from those fixtures. 

Several things cause leaky overflow drains:

• Drain fittings
• Overflow tubes
• Gaskets
• Drain traps

How to fix a leaking overflow drain

If your gasket is the problem, it’s a reasonably easy fix. However, if you’re not confident, call a plumber before attempting to work on your bathtub.

Replacing a gasket is similar to replacing a washer on a tap. You may need some silicone grease, designed for use in plumbing, to lubricate the gasket enough to fit into the drain hole.

I recommend DANCO Waterproof Silicone Faucet Grease (link to Amazon). It’s specialized for plumbing and acts as a sealant, as well as a lubricant. You can buy a single tube or a pack of three tubes, and it’s also safe to use around drinking water.

1. Unscrew the cover plate of the overflow drain.
2. Pull out the plate and the drain plug.
3. Remove the old gasket.
4. Lubricate the new gasket (make sure you’ve bought the right kind for your drain).
5. Fit the new gasket into the hole. If it’s beveled, ensure you fit it the right way around. 
6. Make sure you have a tight seal.
7. Replace the drain plug and cover, and screw back in.

What If I Don’t Want an Overflow Drain?

Some bathtubs, such as freestanding or clawfoot tubs, look better without an overflow drain. You can install a floor drain instead, so that any overflow gets drained away properly, instead of damaging your floors and potentially ceilings.

Note: before installing a tub without an overflow drain or modifying your tub’s existing overflow drain, check local building codes. You can also research Uniform Plumbing Code if planning for new construction.

If your bathtub is fitted to a wall, the plumbing can be hidden inside the walls, and you have no unsightly pipes or tubes visible.

Nevertheless, even if your plumbing is hidden, you might still want a deeper bath than your overflow drain will allow. This is easy to rectify by fitting an overflow drain cover.

Overflow Drain Covers

Overflow drain covers come in a wide range of styles. The Gorilla Grip Premium Bathtub Overflow Drain Cover (link to Amazon) is available in four colors; Blue Transparent, Gray Transparent, Clear Transparent, and White Opaque.

It’s also super easy to use; you just need to moisten the suction cups and press it over your drain. 

Some overflow drain covers require a bit more installation. You can purchase some that need screwing in, some that offer a twistable on-off function, and some that replace the overflow drain with rubber. 

Floor Drains for Freestanding Bathtubs

An excellent way to manage overflow with a freestanding tub is to install a floor drain. Floor drains look like large plugholes, but they’re flat.

You can purchase some floor drains that replace a tile on your bathroom floor, so they’ll blend in, and you won’t be left with an ugly drain in the middle of your tiles.

My grandparents had an ironcast clawfoot tub that you could fill to the rim. As a child it was like having a swimming pool in the bathrooom. The key to this was

1. A recessed floor in the bathroom, and
2. A slightly sloped floor that was designed to move excess water to a floor drain.

In new construction, this could potentially be an excellent alternative to traditional overflow drains, assuming building code allows for it. It’s not quite as practical in a remodel though.

Housing and Contents Insurance

If you do have flooding or water damage from an overflowing bath, you’ll want adequate insurance to cover the costs incurred. Renters who have to provide adequate insurance as a condition of their tenancy will find this even more important.

All insurance policies have exclusions, though, so double-check you’re covered for water damage, especially if you plan on removing or blocking an overflow drain.

If in doubt, call your insurance company and determine if they will still cover you if you’re using an overflow drain cover.

If they agree, don’t rely on a phone call; get it in writing. That way, there can be no doubt when you make a claim.

It’s also essential to check what the excess is on your policy. The excess is the amount you have to pay before the insurance will payout.

For example, if your water damage costs come to $500, and the excess on your policy is $150, you will only get $350 in the payout. The first $150 is your responsibility.

If the excess is likely to be unmanageable for you, switch to another insurance provider.

Renters should always check with their landlord before making any changes to their bathrooms or plumbing. The absence of written permission from the owner of the property could void your insurance policy.

Final Thoughts

Having a bathtub without a drain requires planning to prevent flooding issues. In certain circumstances, if building code and the home’s construction allow for it, floor drains with sloped floors can be a solution.

Ultimately, it is advisable to consult a professional plumber or work with your new home contractor to ensure that you are protecting your property and adhering to building codes.

Related Reading:

Can A Home Improvement Contractor Pull Permits?

Is Green Board Required by Building Codes?

Does a Bathtub Need a P-Trap?