"CS" wrote:

I am looking at getting some water filters, 20 inch housings, with
3/4
inch NPT female connections in plastic tops. Can I get away with
screwing in 3/4 BSP taper male brass compression fittings, using a
good wind of PTFE tape??

No.

NPT is a tapered thread.

BSP is a straight thread.

You cann't get there from here.

Lew