can a toilet and sink share the same drain

Can A Sink Share A Drain With A Toilet

The water from your sink and toilet ends up in the same place as the drain pipes join the lateral line or lateral connection, which is the last pipe. With that in mind, it seems easier and more affordable to use the same drain for your fixtures, but can a toilet and sink share the same drain?

Your sink and toilet can share the same drain but make sure you prevent backflow of wastes by installing the backflow preventer. This plumbing style is often seen in current US regulations. 

Remember, it’s important to have proper drainage, and that means being on top of things to ensure your system works. Well, continue reading to learn if you should use one drain for your sink and toilet and how to do it properly.

Does Wastewater From Your Toilet And Sink End-up In Different Places?

Wastewater from your sink and toilet drains to one place. Initially, the water goes through the device pipe, then the p-trap and pushed by gravity past it to the drainpipes then downwards via the tubes with the help of the vent system.

The drain pipes from your home finally join the lateral line, also known as the lateral connection. This is a residence’s biggest plumbing system with a diameter range of 1 ½ inch to 2 inches. 

The lateral line relies on gravity to drain the wastewater, and it lies in a slanting position to allow the waste to keep moving downwards. Moreover, the water can get out of your home and your residence through the garden.

The lateral lines then join the metropolitan sewer lines. The lower lateral refers to the pipe connection portion away from your home, while the upper lateral is the part in your home. 

Can A Toilet And Sink Share The Same Drain?

As mentioned earlier, you can use the same drain for your sink and toilet. You just need to join the lines beneath your bathroom then develop a vent to facilitate the drainage of waste.

Connect a drain tube to a stack, making it the vent that runs upward via a roof. You also need a drain that moves downwards to your facility sewer. 

Remember that you should not connect the sanitary sewer and drinkable water directly. In addition, you must also prevent wastewater backflow, which entails removing the laundry tub’s hose. 

Moreover, put backflow prevention on the feed tube leading to the external spigots and the boiler. Ensure there’s air space for your softener and the condensate drains and that the air gap designed for the dishwasher drain holds it up high. 

Backflow prevention is essential because certain conditions such as opening the primary water break or the fire hydrant can cause water siphoning to the mains, bringing contaminants. Therefore, don’t be the reason for contaminating your whole neighborhood.

Read also how many toilets on a 3 inch drain

Why Should You Use The Same Drain For Your Sink And Toilet?

While it’s possible to join your sink and toilet drains, you should explore whether it’s a good idea or you are better off separating them. Well, here are reasons to do so:

a) It’s More Practical

Using the same drain for your sink and toilet offers you more convenience than separating them. Dealing with every bathroom fixture as individual lines gives you more work during the execution and planning stages. 

Separating the sink and toilet drains means mapping out how every appliance’s pipes will fit throughout the structure of your home without getting the way of each other. Additionally, sometimes you’ll need to figure out how to include extra PVC tubes in a pipe network that’s already crowded.

Connecting the sink and toilet drain lines lowers the installation and planning time.

b) It’s More Budget-Friendly

Besides easing the installation work, using the same drain for the sink and toilet is also kind to your finances. This approach is more affordable than laying down separate drain pipes for your toilet and sink when you think about it in terms of labor time and the cost of parts needed for the job. 

See also can you replace a 14 inch rough in toilet with a 12 inch rough in toilet

How To Be Connect The Sink And Shower Drain

So, now that you have decided to have the same drain for your sink and toilet follow the following steps to accomplish the project. 

  1. Join The Drain Pipes

Begin by joining the drain pipes of the sink to the toilet’s drain pipes using a two to three inches sweeping y connector. Ensure the sink drain goes via the bathroom drain from the top.

Moreover, the sink drain needs a 2-inch gap to run upward from the 3-inch horizontal pipe in order to prevent backflow.

  1. Cut Out The Drain Pipe’s Three-Inch Section

As you cut your drain pipe’s three-inch section, tie the 2” sink vent. Once you do that, secure the connection with a prep liquid and PVC glue.

  1. Cover The 3-Inch Drain Pipe

Before connecting the pipe to the main sewer duct, cover its end. Examine the connection by flushing the toilet and recharging the lines; this step will help you discover any leakages and fix them before wrapping up the installation.

Remember that it’s better to call a professional if your knowledge of plumbing systems is limited to avoid making a mess of things. Internal plumbing is a mystery to many people, so hiring an expert to connect your sink and toilet drains is a smart move if you want things to be done correctly.

However, if you are up for the task, make sure you understand your drainage and pipe positioning. Your local area building codes will give the necessary information about specific regulations for the fixtures positioning and the recommended distance between waste pipes. 

See also Best 3 inch fit in toilet flange

Conclusion

Your sink and toilet can share the drain; in fact, it makes plumbing convenient, more affordable, and less time-consuming. However, you must ensure it’s done correctly to ensure no backflow and the wastewater is drained correctly. 

Keep in mind that a well-functioning home has an excellent drainage system, so prioritize that before you endeavour to cut costs. 

Read also How to fix toilet flange too close to wall

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