Longest time before emptying black tank?

FireGuard wrote:
I'm posting here as I figure most full timers or boondockers have 5th wheels.
I have a 21' Toyhauler with 58 gal holding tanks and keep it on my 5 acre lot as I develop and build.
I have a water supply and can dump the Grey on the ground but I only spend 1-2 nights a week in it and only use the toilet in the morning and once or twice at night as I water the trees when I'm outside working.
I could probably go a couple of months before filling it but curious if there is a point where it gets nasty.
I haven't noticed and smell or issues so I'll wait until I take it camping and dump before bringing it back up.
Thanks.

While normal RVing in various sites and RV parks, I can go 8-10 days before dumping. My concern in your situation is the possibility of developing the dreaded solid poop pyramid and then be faced with not being able to dump. RV toilets/tanks need sufficient water to avoid having your tank plug up. What do your black tank gauges indicate. you might consider having your tank pumped out.