Here’s Why Kitchen Sinks Don’t Have Overflow

No one can argue the importance of a functional sink in the kitchen. But if you look closely, kitchen sinks are constructed differently from their bathroom counterpart. One key difference between the two is the presence of an overflow in a bathroom sink and the absence of one in a kitchen sink.

Kitchen sinks don’t have a traditional overflow because they usually have an extra basin that catches the overflow. The double basin system has a center divider marginally lower than its overall rim. When the water reaches the height of one basin, excess water will be displaced on the other one. 

Still, it is worth asking if kitchen sinks should require an extra overflow hole or valve. After all, you can never too short of features that prevent water spillage.

If you have the same question in mind, lucky for you, we have the answers right here.

What Is a Sink Overflow?

Sink overflow is a simple mechanism that prevents excess water from spilling outside the basin. Instead of the water going directly to the floor in case of overflow, it is directed to the drainage. It goes through a valve or a hole that is usually found below the faucet or on the topmost part of the basin.

Bathroom sinks and even tubs commonly have this valve. Kitchen sinks, on the other hand, either have a hidden hole in the partition between the two basins or a lower divider that allows excess water to transfer to the other basin.   

Do Kitchen Sinks Need an Overflow? 

Since kitchen sinks are mostly designed to have two basins instead of one, manufacturers didn’t believe that an overflow is necessary.  

Having an extra basin already performs the function of an overflow valve. It catches the surplus water from the other basin thus preventing spillage.

Likewise, considering that the kitchen sink is an area involved in food preparation, it is unsanitary to have an open sink overflow hole that allows air from the drainage to escape. 

Bacteria, molds, and other disease-causing microorganisms can contaminate meats that you’re defrosting or vegetables you’re washing in the sink.

Nonetheless, the need for an overflow all boils down to the overall form and general use of the kitchen sink. Not to mention your own discretion.

Some homeowners opt to modify their sink. They add an extra valve on one basin to maximize the prevention of overflow. But this decision is typically made to increase functionality.

Evaluate the kind of kitchen sink you have according to the following and decide if an overflow is necessary.


Not all kitchen sinks come with a double basin. Single basin sinks usually have deeper bowls to hold large volumes of water to prevent overflow. 

If you wish to add an overflow valve in your kitchen sink just make sure that the opening is not too wide to easily maintain sanitation.


Clearly, the smaller a single bowl kitchen sink is the more necessary an overflow valve is. However, this is not the case for most commercial kitchen sinks. 

Those who have theirs specially made or embedded in the counter may have a different case. Nonetheless, if you feel like the bowl is too small and the likelihood of overflow is high, then you can opt to have your kitchen sink modified.

Kitchen sink overflow is not normally a feature that you should lose sleep from. Manufactured sinks for kitchens are engineered to maximize their capacity in holding large quantities of water without sacrificing their hygienic requirements.

In the same way, cases of sink overflow primarily depend on how you manage your water use and prevent clogging in the drain.

What Causes Kitchen Sink to Overflow?

Instances where water in the kitchen sink overflows are on a case-to-case basis. Due to the large size of the sink basins and limited water use, thanks to the invention of dishwashing appliances, the incidence of water spillage is rare.

However, the moment that overflow occurs, the effects can cause serious harm to your home.

A critical consequence of sink overflow is water damage.

It could destroy your furniture, electrical appliances, and increases the risk of mold and mildew growth. It could also affect the structural integrity of your house and mess up your wiring system.

Repairing the parts of your kitchen affected by water damage can be expensive. It could set you off your budget.

But what exactly could trigger an overflow in your kitchen sink? We know for a fact that water spilling on the floor is not a common occurrence.

Here are certain incidences that could lead to kitchen sink overflow.

1. Leaving the Faucet Open

Whatever reason that could drive you to this point, it is important to remember that kitchen sinks, despite being designed to hold a large amount of water, have limitations.

2. Clogging the Drain with Food Scraps

Leaving food scraps and letting them go down the drain is a common cause of clogging in the kitchen sink. Small pieces of leftovers can accumulate over time and block drainage. Clogging delays, the flow of water and could keep it stuck in the basin.

3. Disposing Grease and Oil in the Sink

Grease, fats, and oils, despite their fluid appearance, can solidify over time especially during colder seasons. If they are disposed of in the kitchen sink, it could eventually form a blockage in the draining tubes.

4. Faulty Faucet

A faulty faucet that goes out of control could cause a lot of damage if not caught on time. Likewise, a sink overflow may not even suffice the water surge.

How to Handle Overflow in the Kitchen Sink

Before overflow occurs in your kitchen sink, you would notice the change in the flow of water down the drain. The slower it gets, the more likely that the blockage gets wider in the drain line. Naturally, stagnation of water is the ultimate sign that you need to unclog the drain immediately.

If overflow becomes inevitable in the kitchen sink, do the following actions.

1.       Turn of the faucet or the service valve.

2.       Get some towels to absorb water on the counter or the floor.

3.       If large amounts of water have already spilled, grab a pitcher and scoop the water. Dispose of it on the toilet or outdoor.   

4.       Use a plunger in case clogging is the cause of sink overflow.

5.       Clear the drain trap by using a wire or a plumbing snake. You can also uninstall it to empty the water in the pipes and remove the blockage in the disposal line.

6.       If grease is the culprit of the clogging, use hot water and salt to dissolve it.

7.       Pour a cup of baking soda followed by another cup of vinegar to create fizz and unclog the drain. Add some hot water to remove stubborn food scraps.


Kitchen sink overflow systems are designed differently not just to prevent water spillage but to ensure sanitation and safety during food handling. The choice to modify a kitchen sink by adding overflow valves requires careful consideration of its general structure and use.

Nonetheless, the absence of a traditional overflow valve in a kitchen sink does not imply that drainage is less efficient. After all, the likelihood of overflow still depends on how much water you use and your disposal strategies in the kitchen.

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