Can I vent into the Existing Black Tank Vent

The short answer is Yes you can.

But this is an advanced, optional modification and must be done carefully to ensure proper function, safe airflow, and long-term moisture management.

Every Nature’s Head toilet comes with a 1.5m vent hose featuring a black rubber end that fits perfectly over 20mm PVC pipe. This makes it easy to connect directly to standard plumbing components.

In some builds installers have chosen to connect into their existing black tank vent instead of creating a separate exit for the toilet vent.

This approach can:

• Reduce the number of wall or roof penetrations

• Route ventilation through an already elevated escape path

• Consolidate airflow channels into a single external outlet

Important note:

It is important to understand that this is not just a plumbing decision it is also an airflow decision.

The Nature’s Head composting toilet requires a continuous stream of airflow to:

• Dry out the compost medium

• Prevent excessive humidity buildup

• Ensure oxygen circulation for healthy aerobic composting

• Eliminate odor before it ever becomes an issue

That airflow comes from the built-in fan, which pushes air through the vent hose and out of your system.

Tapping into a shared vent stack can disrupt that airflow if not planned properly.

Tips for Installation:

For those who understand the risks and plan their plumbing carefully, here’s a general approach:

1. Locate your black tank’s vent pipe – usually a vertical PVC pipe running from the tank up to the roof.

2. Install a PVC Tee in that vertical run, ensuring you never connect directly to the tank or below the trap.

3. Use PVC reducers/adapters to transition down to 1-1/4″ PVC for compatibility with your vent hose.

4. Ensure an upward path from the toilet to the vent, so airflow continues outward and doesn’t stall.

5. Flush and clean your black tank thoroughly before install to reduce risk of backdraft odour.

Tips to Maintain Moisture Balance

If airflow is compromised, composting stops and moisture builds up. But if airflow is well-managed, this method can be a clean and stealthy solution for certain builds.

• Never use this setup without an active fan. The fan must run 24/7 to maintain airflow direction and pressure.

• Consider using charcoal filters in the vent path to prevent potential backflow.

• Monitor humidity in the solids bin. If you’re seeing condensation or a runny compost medium, you may need more airflow or a separate vent run.