How to Vent a Saniflo Upflush Toilet

Installing a basement bathroom can improve your home’s value. However, if roughed-in plumbing hookups are not in place, installing traditional plumbing can be both expensive and laborious.

Fortunately, one alternative is available; an upflush toilet with a self-contained tank that allows water and waste from the toilet, sink, and shower.

Just like the drain line or waste line in your home, an upflush toilet should vent into the house’s main vent stack, which often extends from the main sewer line up through the roof. Upflush toilets like saniflo come with a pre-installed vent connection on the top of the tank.

How Do You Vent an Upflush Toilet?

Things You’ll Need

  • PVC pipe
  • PVC corner fittings
  • PVC T-fittings
  • PVC cleaner and glue
  • Hack saw
  • Drill with a 2-inch hole bit
  • Tape measure

Procedure to Follow

Step 1: Locate Main Sewer Line and Vertical Vent Stack

First, find the main sewer line and the vertical vent stack which often runs from the sewer line up through the walls and exits out of the roof. Usually, it is a 4-inch pipe commonly referred to as a vent-and-soil stack. Although water and waste from upper floors flow into the vent-and-stack, the pipe also serves the purpose of the house’s vent system.

Step 2: Locate the highest wastewater drain connection on the vent-and-soil stack

Once you locate the main drain system and the vertical vent stack, now it is time to find the wastewater drain connection located highest on the vent-and-soil stack. Ideally, it should not be higher than the uppermost floor with a kitchen sink or toilet. Connect the vent pipe from your upflush toilet to a point on the vent-and-soil stack upper than this drain connection. Preferably, connect the vent line in the attic.

Step 3: Locate the vent connection on the top of the upflush tank

With the vent pipe connected to the vent-and-soil stack, come down to your upflush unit and locate the vent connection. This is certainly the 1-1/2-inch fitting on the upflush tank. Make sure all your plumbing fittings and the diameter of the PVC pipe you will use are of the same size as the vent connection on the upflush tank.

Step 4: Install the PVC pipe

Connect the PVC collar fitting followed by the PVC pipe on the vent opening on the upflush tank. The PVC pipe should stretch between the wall studs to the attic. Use a drill with a 2-inch hole bit and make a hole, ideally, in the wood plate between the floors. You can let the vent line pass through the floor to the vent-and-soil stack. Make sure to use PVC cleaner and glue for all pipe connections as advised on the containers.

Step 5: Install the corner fitting

Install the PVC 90-degree corner fitting by attaching it to the top of the upflush vent pipe in the attic. Equally, attach a horizontal line to reach the vent-and-soil stack.

Step 6: Connect the 4-inch to the 1-1/2-inch reducer T-fitting

Install a 4-inch to the 1-1/2-inch reduce T-fitting on the vent-and-soil stack. You can do this by cutting the stack pipe with a hack saw, then inserting both ends of the stack into the large fitting opening. However, the smaller 1 ½-inch T-connection should be attached to the upflush vent pipe.

Things to Note

If the proximity of the vent-and-soil stack is near the pipe for the upflush vent, you might be able to run the new vent line adjacent to the stack in the same wall. Also, don’t connect the upflush vent to the vent-and-soil stack below the lowest wastewater drain connection.

Does a Saniflo Toilet Need to be Vented?

Yes. All Saniflow toilet products require a 1-1/2-inch vent pipe, which must be vented to the main vent stack according to the local plumbing code. However, the Sanicompact 48 and Sanistar models don’t require any venting since they are considered self-contained toilet units. Also, it is not recommended to use an air admittance valve or a mechanical spring-loaded device as they allow air to flow in one direction.

Do You Need to Vent a Basement Toilet?

Venting a basement bathroom can be challenging because you have to take extra caution so that you don’t damage the basement pillars or other parts of your building. Although it is easy to vent in new construction, it is quite difficult to vent when you make your basement toilet in an already existing basement. So, do you need to vent a basement toilet? Yes, it is necessary. Below is a guide on how to vent a basement bathroom.

Step 1

If you have prerequisite knowledge and skills in plumbing, you can try a DIY. However, if you don’t have any ideas, hire a professional plumber to help vent your basement bathroom toilet. if you decide DIY way, then the first thing to do is to call a civil engineer and have him decide the best installation site for your basement bathroom toilet.  For everything to work well, you need to make everything proper and at the right installation site. Hence, take the engineer’s recommendations seriously.

Step 2

With the civil engineer’s recommendations, acquire the required materials to install an appropriate ventilation system. Start venting your basement bathroom once your bathroom framing walls are up. Ideally, it is easier to vent installation from this point, since the vent pipes will run below the floor joists. Besides, you will want to hide the ventilation pipes by lowering the basement ceiling.

Step 3

If you already have a sewer gas line in place, then connect the vent lines with the existing lines. With the ventilation system of the upper floor in place, the entire process of venting your basement bathroom toilet becomes even easier. Seek the help of a plumbing inspector to get the right vent system materials.

Equally, read the plumbing codes of your local area since these codes vary from one area to the other. Take the procedure we discussed above for this type of installation. Most importantly, ensure that the vent-and-soil stack is fixed at least 6 inches above, from the highest fixture as per the plumbing codes.

Step 4

Installing a fan in your basement is equally a great idea for better ventilation in your bathroom. To install the fan, make holes with a drill machine in the ceiling and securely fix the fan. Connect it to a power source and ensure it runs as desired.

Ideally, install the fan between the shower and the toilet for proper air ventilation. However, if your basement ceiling is too hard to make holes or you don’t want the risk of holes in your basement ceiling floor, consider installing a wall fan, which is a better alternative.

Step 5

Installing exhaust fans is also a great idea for the vent system of your basement bathroom toilet. in this case, get small or medium-sized exhaust fans and install them strategically in your basement bathroom to improve ventilation. One or two exhaust fans are good to ensure the bathroom’s wet air is evacuated and the basement bathroom remains fresh and dry.

Can You Poop in Saniflo Toilet?

Yes. You can actually poop in a Saniflo toilet. Just like the normal toilet systems, you can poop or put any organic waste into your Saniflo toilet bowl and use its flushing mechanism to flush it down the drain. The organic waste may include toilet paper, which like in normal toilets can cause blockages in Saniflo toilet units. Other materials that can clog your Saniflo toilet include sanitary pads and baby wipes. Ideally, flush your Saniflo toilet at least once a day.


Q: Will I need a vent for my Saniflo Macerator Pump?

A: Sanicompact comes with a self-venting system, therefore, it doesn’t require venting or connecting to a vent stack. Nonetheless, other fixtures may require venting as per the local plumbing codes. It is recommended for your macerator pump to be linked to a ground fault interrupter (GFI) circuit.

Q: How large is the discharge pipe on a Saniflo pump?

A: The size of the discharge pipe on a Saniflo pump depends on the pump model. As such, a discharge line can either be 3/4 or 1 inch in diameter while the Sanicubic range uses a 1-1/2 – inch diameter discharge pipe.

Q: Why does my upflush toilet smell?

A: Bad smell from your upflush toilet is often occasioned by the build-up of limescale and human waste in the 2 inches of water that is often left in the Saniflo bowl. To find out if it is your Saniflo toilet that is emitting the bad smell, flush it or refill your basin with and pour it in.


Regardless of the size of the house, venting a Saniflo Upflush toilet in your basement will improve healthy breathing in your home. If you are not a skilled DIY-er, consider hiring a professional plumber to help vent your upflush toilet in your basement bathroom. But if you want to DIY, then we hope these steps we have mentioned above can come in handy.

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