Hi Dave,
thanks. I think I will then just use https://www.diagrams.net/ (previously draw.io) which is open source and web based. It has lines and boxes etc. Though, I wished it also had some more specialized symbols for an irrigation plan like sprinklers and valves (though, it seems to have way too special symbols like hydraulic stuff like a “Gate Valve (Spring)”.
But I can “mis-use” some of the symbols for that. Will work for me. Thanks.