I see posts about this subject fairly regularly and wonder how I'm still alive. I grew up rurally and have never had a first flush system or a filter in my rainwater, the house I'm in now has a grill to stop pine needles and that is all. We drink out of puddles and seeping springs while we're hunting as we travel very light. I think if you acclimatize your body it will handle a few bugs no trouble. I'm statistically more likely to roll my quad or tractor at work than poison myself through the water here.
I live in central Florida and am building an off-grid tiny house. Designing a water system has been my main challenge (and main obstacle to moving to the location I intend). Reading this thread has been very informative.
On one hand, I'm contemplating paying to have a well professionally dug, and let that be the end of it, but I would prefer to have a self-built system drawing lake water and using a slow sand pre-filter leading to ceramic filter (such as the Monolithic ones mentioned above).
I'm trying the find the sources to answer these questions.
1. Is my lake, spring-fed (from below, as is almost all of Florida's lakes) and a near perfect circle 660 ft across, large enough to be a good source?
2. If so, where exactly in the lake should I draw from? The center surface? The center below the surface (and how far below)?
3. Where can I find plans to build a slow sand filter suitable to my low-level needs (only one person's worth of water)?
Also on ceramic filters, I know there is this organisation, potters for peace: https://www.pottersforpeace.org/ that teach how to make your own ceramic filter, so it does seem possible to make this without outside dependency.
Also another interesting filter mechanism I have read of is the sari cloth filter, where 4 layers of a specific cloth are very good at filtering water. Maybe not something one wants by itself, but might be interesting in combination with other filters.
So I do feel there is a lot of potential for local, electricity-free filtering systems, just that there is not that much resources to be found yet. But I suppose as with so many things as long as energy is cheap, it is much easier to make money out of non-local systems that do use electricity.
Another interesting one I just found that talks about slow-sand filters, as well as biochar filters as well as biochar augmented sand biofilters: https://www.nature.com/articles/s41598-020-57981-0 In these tests it seems that biochar and biochar-sand filters worked best.