Installing a toilet in a basement or other below-grade area can be a game-changer for anyone looking to add a more functional space to their home. However, the process is a bit more complex than installing a standard toilet on above-ground floors.
In this article and accompanying video, This Old House plumbing and heating expert Richard Trethewey shows us how to install a below-grade toilet system, reviews the design’s unique components, and covers the various considerations involved.
Understanding Below-Grade Toilet Systems
Below-grade toilet systems overcome the challenge of moving waste upward and against gravity. These systems use specialized equipment to pump waste to the main sewer line, allowing you to install toilets in basements and other underground areas.
How Below-Grade Toilets Work
A below-grade toilet system consists of several key components:
- Electrical connection: As you might have guessed, these parts power the toilet’s macerator pump.
- Macerator pump: This device grinds solid waste and pumps it upward to the main sewer line.
- Small-diameter discharge pipe: This pipe is typically 3/4 inches in diameter, much smaller than the 3-inch pipe used for standard toilets.
- Specialized toilet: Unlike standard toilets, these units discharge waste horizontally through the back instead of down through the floor.
The macerator pump is the heart of the system. When waste enters the pump’s reservoir, sensors activate the grinding mechanism, which breaks down solids and pumps the resulting liquid upward through the discharge pipe.
Pros and Cons of Below-Grade Toilet Systems
Below-grade toilets offer several benefits:
- Flexibility in bathroom placement
- Improved living space utilization
- Increased home value
- No need for extensive excavation or plumbing modifications
These systems can pump waste up to 16 feet vertically and 150 feet horizontally, providing plenty of range for most residential applications. While below-grade toilet systems offer many advantages, be aware of these potential drawbacks:
- Higher installation costs: Specialized equipment and the complexity of the installation process contribute to higher upfront costs.
- Maintenance needs: These systems have more components than standard toilets, making them more prone to wear and tear.
- Potential for mechanical failure: Integrating electrical components introduces the risk of mechanical failure, which could lead to costly repairs.
Installation Process
Installing a below-grade toilet system requires careful planning and execution. While we recommend professional installation, understanding the process can help you make an informed decision.
Preparation
Before installation begins, remember to take these steps:
- Choose an appropriate location
- Ensure access to electrical power
- Obtain necessary permits
- Plan the route for the discharge pipe
Component Installation
The installation process typically involves the following:
- Connecting additional fixtures (if desired)
- Connecting the toilet discharge to the macerator
- Installing the small-diameter discharge pipe
- Mounting the specialized toilet
- Positioning the macerator pump behind the toilet
- Wiring the electrical connection
Connecting to Existing Plumbing
The final step is connecting the discharge pipe to the home’s main sewer line, often involving running the pipe up a wall and across the ceiling to reach the appropriate connection point. Additionally, you’ll need to integrate the system’s venting with your home’s existing plumbing vents to ensure proper airflow and prevent pressure build-up in the system.
Choosing Professional Installation
Hiring professionals to install a below-grade toilet system is a good way to ensure the best performance from your system. Qualified plumbers have the knowledge and tools to tackle potential challenges, from securing permits to troubleshooting unexpected issues.
Cost Considerations
The cost of installing a below-grade toilet system is typically higher than that of a standard one. Several factors contribute to the increased expense:
- Additional plumbing: Small-diameter piping is necessary to carry waste to the main sewer line.
- Electrical work: The macerator pump requires a dedicated electrical connection.
- Labor: Installation is more complex and time-consuming than standard toilet installation.
- Specialized equipment: The macerator pump and specialized toilet are more costly than standard fixtures.
While prices vary widely depending on location and specific circumstances, homeowners can expect to pay between $1,000 and $3,000 for a complete below-grade toilet system installation.*
*Cost information in this article sourced from contractor estimates used by Angi.
Budgeting for Future Costs
In addition to the initial installation costs, homeowners should budget for future maintenance and potential repairs. The components of a below-grade toilet system, particularly the macerator pump, can wear out over time and may require replacement. Setting aside funds for these expenses can prevent unexpected financial strain.
Hidden Costs to Watch For
To prepare a comprehensive and adequate budget, homeowners need to account for potential hidden costs, which may include the following:
- Permit fees: Some municipalities require permits for plumbing modifications, which can add to the total cost.
- Structural modifications: In some cases, existing structures may need alterations to accommodate the new plumbing system.
- System upgrades: Older homes may require upgrades to existing plumbers to ensure compatibility with the new below-grade toilet system.
Maintenance and Longevity
Proper maintenance is crucial for the longevity and efficient operation of below-grade toilet systems.
Regular Maintenance Tasks
To keep the system running smoothly, remember these tips:
- Avoid flushing non-biodegradable items
- Clean the toilet regularly with non-abrasive cleaners
- Inspect connections for leaks or wear
- Periodically check and clean the macerator pump
Lifespan and Replacement
With proper care, a below-grade toilet system can last 10 to 15 years. However, depending on usage and maintenance, the macerator pump may need replacement sooner than that. Homeowners should budget for potential repairs or replacements over the system’s life.
Troubleshooting Common Issues
Almost every system may experience occasional issues, and below-grade toilets are no exception. These are some common problems you may run into:
- Clogs in the macerator pump: Pump issues are often solvable with a simple power reset or clearing physical blockages.
- Electrical failures: Regularly checking the macerator pump to ensure it has a reliable connection to power can prevent many electrical issues.
- Leaks in the discharge pipe: Regularly inspecting pipes can help catch and address leaks early.
Alternatives to Below-Grade Toilet Systems
While below-grade toilet systems are a convenient solution for basement bathrooms, there are some alternatives to consider, such as:
- Composting toilets: Ideal for areas without access to municipal sewer systems
- Incinerating toilets: Use heat to reduce waste to ash, eliminating the need for plumbing
- Sewage ejector pumps: Similar to macerator systems but designed for higher-volume applications
Each alternative has its own set of pros and cons, and the best choice depends on your specific circumstances and local regulations.
Sewage Ejector Pumps
Sewage ejector pumps can handle higher waste volumes. They are particularly suitable for homes with multiple lower-level fixtures, as they can accommodate waste from toilets, sinks, and showers.
Composting Toilets
Composting toilets offer an eco-friendly solution by breaking waste down into compost through natural biological processes. These systems work well in areas without sewer access but require regular maintenance to manage the composting material.
Incinerating Toilets
Incinerating toilets use high temperatures to reduce waste to ash. While they eliminate the need for plumbing connections, they have higher energy requirements and may not be suitable for all homes.
