Marine Toilets: The Basics

marine head
Moving up to a boat with a fixed toilet is a great step forward for your family and friends.

One  difference between a “guys’” open boat and a boat intended for mixed company or the entire family is a marine toilet or head. Graduating from peeing over the side or, in a pinch, using a bucket, to a boat with a fixed head means you can stop worrying about the inevitable call of nature for you and your guests, and just relax. If you’re looking to buy a boat with a head, here are some things to consider.

When I managed a large yacht yard, we had a full-time, year-round staff that dealt with marine sanitation systems. It was a nasty job to fix or unblock someone else’s toilet, but it was always in demand, and that group of dedicated pros saved many a vacation by getting the head(s) operating again.

There are three basic types of marine head: self contained porta-pottys that usually cost less than $150, fixed plumbing systems with a holding tanks that cost $1,000 or so, and complex systems that can treat raw sewage so it’s safe to pump directly overboard. These are even more expensive, typically have both power and fresh water connected to them, and unless you’re really handy, generally require service by a trained professional to repair and maintain. For more on this, read Marine Heads, Portable and Pump-Through.

marine sanitation
A simple toilet with a holding tank setup may require hose replacement after a number of years.

Holding tanks are the most common setup, with treatment-system heads usually reserved for larger live-aboard vessels. The trouble with holding tanks is that the typical plastic tank and plumbing hoses can acquire a smell after a few years that permeates the boat, even when the tank is empty. There are a number of deodorizers that you can put directly in the toilet and pump through the system, but on boats over 10 years old you may be better off replacing the tank and/or plumbing than trying to mask the smell. This is not difficult to do and most DIY boaters can use the old system to template a replacement for $200 to $300  dollars. Anyone buying a used boat of any age should consider this one of those inevitable maintenance issues. Tanks are available in almost any size or configuration and if necessary can be made to order. My one suggestion here is to use the higher-grade hoses in your replacement project, the kind that does not absorb the smell easily—and don’t forget to replace the vented loop hose and make sure the vent screen is clear, too. Holding tank systems usually use raw water from whatever you are floating on. The heads in saltwater boats can tend to have more smell than those in freshwater boats, just from the critters and seaweed that pass through the system.

For more details on all of these issues, refer to these three articles:

A self-contained porta-potty may do the trick on a smaller boat for around $100, provided you have some privacy. You’ll have to empty the tank yourself, but many harbors and camping areas now have pump-out stations that can deal with porta-pottys as well as traditional holding tanks.

If you’re considering a boat with a sanitation system that treats sewage before discharge, I recommend you look at the boat’s service records to determine if the system has been kept up to date. Inspection by a qualified pro with that particular brand may keep you from trying to save your vacation down the road. It is absolutely amazing the things landlubbers will try to flush down a marine head, and which ultimately bollux up the works.  A pre-trip word with your guests about toilet etiquette onboard will save you many an uncomfortable discovery.

  • Use biodegradeable toilet paper only!
  • Use in moderation: If it is yellow, let it mellow, if it is brown, flush it down.
  • The fines for overboard discharge of untreated sewage are rising; protect the environment you use for recreation; get acquainted with the local pump-out facilities and personnel.
  • One part bleach to 10 parts water should kill any bacteria in any cleanup.
  • Prior to haulout flush, clean, and pump dry your holding tank. Once on the hard, drain any water in the toilet to prevent freeze-up damage during winter storage.

It’s good to give your family and guests  a more refined approach than a bucket.

An earlier version of this article appeared on Boat Trader in April 2013.