This video isn’t the best but you can kind of see all the pipes.
Our tiny house has tons of pipes under the trailer for holding the bathroom and kitchen wastewater and two valves for draining. (The kitchen wastewater is separate from the shower and bathroom sink water.) It can hold about 60 gallons total or more, we can’t remember the math of all the pipes….The house does not produce any blackwater because we use a composting toilet.
and this is just a cute picture of Yuri working on the pipes.