What Is a Macerating Toilet and When Do You Need One?

What a macerating toilet does

A macerating toilet combines a standard toilet bowl with a pump unit that contains a set of rotating blades. When you flush, the water and waste drop into the pump chamber, the blades grind the solids into a fine slurry, and the pump pushes that slurry through a narrow discharge pipe to your main waste line. The whole process happens within seconds of the handle going down.

The important difference from a conventional toilet is mechanical. A gravity toilet moves waste using the weight of a tank of water falling into a large, sloped drain. A macerating toilet adds an electric pump, so it does not need the same slope or pipe size, and it can push waste upward if the destination line is higher than the bowl.

You will also hear these called upflush toilets, because the pump can move waste up to a higher drain. The concept is the same: grind, then pump.

When you need a macerating toilet

You need a macerating toilet when the drain cannot do the job by gravity. The classic situation is a basement bathroom. A basement floor sits below the main sewer line, so a regular toilet cannot slope down to the street connection. A macerating pump lifts the slurry and sends it up and across to a line that is at a higher elevation, which makes a finished basement bathroom possible without cutting through the floor slab.

Other situations are similar in principle. You might be converting a closet into a half bath, adding a guest suite in an addition far from the main waste stack, or putting a toilet in a room built over a concrete slab. If running a new gravity drain would mean tearing up floors or walls, a macerating system with its thin discharge line can avoid most of that work.

Plumbing codes still apply. A macerating toilet is an approved fixture in most areas, but the authority having jurisdiction sets the rules for installation, venting, and discharge. Check local requirements before you commit to a project.

How the unit handles wastewater

The macerating pump unit is the junction for the bathroom's wastewater. Most models connect the toilet, and many also accept a sink drain; some accept a shower or tub. Every fixture drains into the unit's chamber, the macerator grinds everything together, and the pump sends it out through one small pipe.

Because that pipe can run horizontally or rise vertically, your routing options are much wider than with a gravity system. A gravity drain needs a continuous downward slope and a relatively large pipe, which often forces the bathroom's location. A macerating unit removes that constraint, which is why it is the standard solution for basement and retrofit installations.

A check valve inside the discharge line keeps wastewater from flowing backward into the pump or the bowl. Keep that valve accessible so it can be serviced if anything lodges there.

Water use and efficiency

Macerating toilets do not use extra water. The flush is a measured amount from the tank, just like a regular toilet, and the pump only moves what the flush already delivered. Toilets that carry the WaterSense label flush with 1.28 gallons per flush or less, which is 20 percent below the federal standard of 1.6 gallons per flush.

The EPA points out that toilets are the main source of residential indoor water use, accounting for nearly 30 percent of an average home's indoor consumption. Replacing an older model that uses as much as 6 gallons per flush with a WaterSense labeled toilet can cut toilet water use by 20 to 60 percent, saving nearly 13,000 gallons per year for an average family. Those figures apply to any toilet, including macerating models, so the efficiency logic is the same as for a standard fixture.

What to look for when buying

Start with the flush volume. Look for a model that uses 1.28 gallons per flush or less, and check whether it holds the WaterSense label. Then check the pump's rated discharge: the manufacturer's spec sheet tells you the maximum vertical lift and the maximum horizontal run, and your installation has to stay inside those limits. Our roundup of the best macerating toilets compares models on specs, and the upflush guide focuses on compact systems.

The bowl still matters. Macerating toilets come in round and elongated shapes, and in standard and chair heights, so the same ergonomics you would compare on any toilet apply here. Measure the space and check the rough-in if you are replacing an existing fixture. Our guide to measuring the rough-in walks you through it, and the toilet seat height guide explains the options.

Compare the overall design the same way you would any other toilet. Decide between a one-piece and a two-piece layout, and think about the materials and finish in the room. The spec sheet can look dense, so read how to read toilet specs before you compare models.

Installation and maintenance

Installing a macerating toilet is closer to wiring a small appliance than to laying a large drain line. The unit plugs into a standard outlet, the toilet connects to the pump unit, and the discharge pipe runs to the nearest waste line. For the general steps, see how to install a toilet, and check the water supply pressure against the toilet's rating, as explained in toilet water pressure requirements.

Maintenance is modest. The cutting mechanism is self-contained and designed to clear itself with each flush. Use only toilet paper and human waste, and never flush wipes, paper towels, or other items that do not break down; they are the main cause of clogs in the small discharge pipe. Also keep the shutoff and the check valve accessible so a plumber can reach them if needed.

What to pick for your use

Questions

How does a macerating toilet work?

It grinds waste into a fine slurry with an electric cutter, then pumps the slurry through a small discharge pipe to the main waste line. The pump runs automatically for a few seconds after each flush.

Can a macerating toilet be installed in a basement?

Yes. Basements are the most common application because the pump lifts waste upward to a sewer line that sits above the floor.

Does a macerating toilet use more water than a regular toilet?

No. The flush volume is the same as a regular toilet, and many models meet the 1.28 gallons per flush WaterSense target.

Is a macerating toilet noisy?

The pump makes more sound than a gravity flush alone. It runs briefly after each flush, so the added noise is noticeable but short-lived.

Do I need a special sewer line for a macerating toilet?

No. The unit connects to the existing waste line with its own small discharge pipe. You do need an electrical outlet nearby to power the pump.