Seasonal or not, you're asking for trouble if the black valve is left open.
Dumping at a seasonal site should be no different than any other.
2011 351RLTS Eagle, Mor/Ryde suspension & pin box
06 F350 Lariat PSD, SRW, LB, CC, EGR delete kit, 16K DrawTite hitch, Timbrens, TST TPMS
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