Have you noticed the small hole on top of your kitchen sink, laundry, and bathroom basins? Well, it's not just a random hole. It is designed for a purpose and is called an overflow hole. In this article, we will explain more what this hole is and how it works. We also give some tips on keeping your overflow hole clean.
The sink overflow hole is simply an opening that directs the water into the sink overflow system. The sink overflow system is a hidden channel running behind and under your bathroom sink. Chances are you've never seen the channel in your entire life. At the top of the channel is the visible sink overflow hole.
Depending on the design of your sink, it may have one, two or three holes, and they may appear between the faucet valves, facing toward you, or under the near rim, facing the mirror. They serve two functions: to prevent an overflow with the drain stopper engaged and to provide an escape route for air in the drain.
The overflow opening serves two important functions: If the water tap is left on while the drain stopper is closed, the opening will channel water down into the drain opening rather than letting it spill out of the sink onto the floor.
An overflow opening is a small hole drilled in the top of the threaded portion of the drain that allows overflow water from the sink to enter the drain pipe. If your sink features an overflow, it is very important to purchase a drain with an overflow opening so that your sink and drain function properly.
According to the U.S. Geological Survey, there are three common types of sinkholes: 1) dissolution, 2) cover-collapse, and 3) cover-subsidence.
The bottom line is that it is not a necessary feature to have in your kitchen or laundry sink. This is because the drainage pipes in sinks are generally sufficient enough to allow for water to drain smoothly, as long as there are no plumbing issues such as obstructions in the drain pipes or clogging.
A 3-hole sink is very common in bathrooms. Depending on the spacing of the holes, you can choose a centerset, mini-widespread, or widespread bathroom faucet. A 2-hole sink usually accommodates a 4” centerset faucet. This is the easiest bathroom faucet to install or replace.
The first obvious reason is simple: It is very tough to overfill a kitchen sink because they are so large. Also, since most kitchen sinks are two-bowl designs and the divider is lower in the middle than the sides, the second bowl will act as a backup for any spilled water, and an overflow would go down that drain.
Thankfully, avoiding a sink flooding isn't hard to do; you just have to keep in mind that most water overflows happen due to a clogged drain. If you easily maintain it by keeping your drain clear, water should be able to flow to the sewers as intended. If not, you may end up dealing with some over flowing water.
It's an opening which can prevent a flood in the bathroom. It is a preventative measure and there are no plumbing codes to regulate the need for installing a basin with an overflow hole. But this could change, so it's best to check with your local licensed plumber at the time of installation.
In many cases you can simply examine your faucet and count the holes. If you have separate handles for hot and cold, you have three holes in the sink. Measure the distance between the handles. Hold the the tape measure above the faucet if it's in the way.
There are three common drain sizes for bathroom sinks, 1.25", 1.5" and 1 5/8 (1.625"). You need to select a drain that is the same size or SMALLER than the hole in your sink. For example, if you have a sink with a drain hole of 1.75", than any of the drains 1.25", 1.5", or 1.65" will work.
Solution sinkholes have sides that vary from gentle slopes to almost vertical, while their shapes include saucer-like hollows, cones, cylindrical potholes and shafts. Streams or rivers may enter a sinkhole and disappear underground. This type of sinkhole is often called a swallow hole.
A bit of baking soda and white vinegar does work. And absent a handy squeeze bulb and tube, a turkey baster will suffice to get things down into the often-tiny overflow drain openings in wash basins. You can use a dry turkey baster to squirt in a few teaspoons of baking soda followed by about a half cup of vinegar.
A smelly sink is usually caused by bacteria build up from grease, fat and food which have been flushed down the drain. These will then get stuck in the pipes causing the familiar rotten egg smell.
The water leaves quickly and the tank begins to refill. As the tank refills, some of the water goes from your fill valve through the refill tube and in the overflow tube. The job of the overflow tube is to empty the water directly into your toilet bowl.
A traditional overflow consists of a hole cut into the tub to accommodate a drain that installs on the inside and outside walls which collect excess water and sends it down a tub drain to a P-trap.
Remove standing water
Use anything you can – a mop, old towels, newspaper – to absorb the water and get it into buckets or down a drain. If you have a wet/dry vacuum cleaner, use that. If you have severe flooding, you may need to call a water damage clean-up service.
The image below is a common bathroom sink with the overflow in the back of the sink. Some sinks have the overflow hole in the front of the sink – same thing just different design. Often this overflow area can collect foul mildew smelling bacteria.
Air gaps for water filtration
Plumbing codes require water softening systems to air gap their drain lines and it's strongly recommended you include an air gap in any under-sink reverse osmosis system. Furthermore, the purpose of these systems is to deliver high-quality water to you and your home.
Try a Snake
A drain snake, also known as an auger, is helpful for placing a long wire down the drain and pushing through anything that may be blocking the sink. Sometimes it can even pull back up things, such as hair or other things blocking the plumbing.