Tax Treatment for HOA dock rental fees

Almost all of our income is exempt (annual HOA dues)from federal taxes. But we rent a few docks to HOA members on an annual basis for 12 mth periods, and have been treating as taxable (nonexempt) income on our Fed 1120-H. Am interested in whether other HOA's handle dock rental income as exempt or nonexempt income.
I've argued with IRS twice, trying to say that under section 1.528-9 (d) special exclusion, this should be considered exempt income like the examples they give of swimming pool or tennis court annual fees. But they keeping maintaining that "rents" must be considered as gross taxable income. Thanks, Chuck

You can call it what you want, but the fact is that it's not "dues" or "memberships" - therefore it's misc. income.

Try to get rid of the income by increasing your maintenance/upkeep costs for the docks.

There are other types of "exempt function" income besides dues (assessments), such as monies received from members for use of an assn's facilities, such as swimming pools and tennis courts.