The port requires that the dive service submit a best management practices plan and then follow it... so any company determining that is in their best management to clean hulls every 3 weeks, will have submitted that on their BMPP form and then be required to follow it...

Sort of an ISO 9000 thing... submit the plan and then follow it and you are good to go.

Well if the dive company Tacoma is using has submitted that best practice is to clean hulls every 3 weeks, then indeed they are required to follow THEIR plan. Other companies however may have other BMPP submissions. Tacoma needs to call around.

The bottom line is that there is no specific regulation telling the dive company that they have to clean every 3 weeks, but there is a requirement for documentation that has to be followed after submission. Neat little catch-22.

Turns out all this only applies to San Diego Big Bay... Mission Bay is exempt (way fewer boats there anyway) and thus the company I use, doesn't have this issue. Of course the other side is that marinas only allow certain companies access to their waters... and thus Tacoma may be limited to companies that have submitted 3 week plans.