Here is the response I received from the Puget Sound Keepers Alliance to the question: "What is the legal standard that prohibits individual boaters from using soap to wash their boats? Where is the list of prohibited discharges that will cause me to be fined or sued for polluting Puget Sound?"

The following response is quite reasonable and is not nearly as difficult to live with as I was led to believe by our Marina management.

Thanks for your question. Unfortunately there is no simple answer, or if there was the short answer would simply be no soaps are allowed to enter the water from boat cleaning. I'll go over the legal aspect first since that is what you asked, and will offer some solutions at the end.

There is not a list of chemicals that are prohibited- essentially all chemicals are prohibited according the Clean Water Act and RCW 90.48.

Generally speaking any entity that discharges pollutants needs an NPDES permit to discharge, it is not up to the EPA to provide a list of prohibited pollutants. These NPDES permits have strict limitations which are usually strengthened every 5 years or so as technology improves. However recreational boaters (under 79 feet) have certain exemptions under the Clean Water Act: As I understand it these include sewage that is treated by Coast Guard Approved devices, Gray water from vessel sinks and showers, engine cooling water (raw water - not coolant), (non-oily) bilge water, and deck runoff from rain. However no exemption exists for boat cleaning.

Ironically an NPDES permit was proposed for boating a couple years ago and the marine industry and boating public fought it back. This permit would have created an approved list of best practices which potentially could have included guidance for boat cleaning. What resulted instead was the Clean Boating Act of 2008, which created or clarified some of the exemptions I described above. Almost no other user group has these exemptions, however there is no approved soap for discharge from boat washing.

This issue can be dealt with a number of ways but if you are looking for a precise clarification under the law you probably will not like what you find.

The prevailing common-sense guidance is generally to select a non toxic soap and to use as little soap as possible so that there are no visible suds on the water (Biodegradable as a practical term is almost meaningless anymore as there are no standards for making this claim). If there are no suds on the water essentially then there is nothing that is a reportable offense. This is the minimum requirement for our Clean Marina certifications. However many of our marinas prohibit soaps altogether as they are technically illegal and have been shown to kill fish even in very small quantities and many marinas find this easier to monitor. They are also entitled to set their own rules to maintain the environment in their marina.

An alternative cleaning method would be to wash the boat with fresh water and hand scrub after a cruise. After the boat dries you can spot clean any stains with your cleaner of choice and wipe up the residue without creating a discharge.