What to draw a plumbing layout in — and what it costs
Four ways and what each gives you
The difference is not how pretty the drawing is — it is how much the tool knows about parts. A pencil knows nothing, CAD knows about lines, BIM knows about objects and calculation, a builder knows about specific fittings and whether they mate.
| Way | What you get | What you do not |
|---|---|---|
| Paper and pencil | Fastest thing there is for one branch; nothing to install or learn | No parts list, no catch on mismatched ends, and any change means redrawing it all |
| General-purpose CAD | Exact lines and dimensions, printing to scale, any drawing at all | A line knows nothing about threads or diameters: you check compatibility, you write the schedule |
| BIM and specialist calculation packages | Hydraulic calculation, documentation, teamwork — what a design office lives on | Price and learning curve; a single flat takes wildly more time than it deserves |
| Online builder over a parts catalogue | The layout is built from real parts, mismatches show up as you draw, the shopping list counts itself | Does not give you approval drawings or a hydraulic calculation |
We build the fourth kind — and below we list what it cannot do.
Choosing by the job
Ask not “which is more powerful” but “what has to exist at the end”. The answer changes completely.
- Swapping a mixer and working out which adapter to buy — a sheet of paper and a thread table will do.
- Doing a flat's layout or a water heater yourself — a builder: it catches mismatches and tells you how much of what to buy.
- A drawing for the plumber, so that what gets built is what you meant — a builder or CAD: what matters is that it can be shown and argued over.
- An apartment block, an approval process, a hydraulic calculation — a specialist package and a designer.
What to look for in a builder
The interface matters least. Three things decide whether it is useful, and all three show on the very first layout.
What we do not do
We do not produce approval documentation, we do not calculate hydraulics to code, and we do not do drainage — the last one is a deliberate decision, not a gap about to be filled.
What we do give is a layout built from real catalogue parts: if it goes together on screen, neighbouring parts mate by thread and diameter, and the shopping list is counted from the same drawing. For a flat, a cabin or a typical house that is enough — most of what people are looking for when they search for plumbing software; a large or unusual system will still need a calculation.
Common questions
What software should I draw a water layout in?
For your own house or flat, a builder that knows real parts and counts the shopping list for you. For drawings that go through approval, a specialist calculation package, usually in a designer's hands. General CAD sits between: it draws anything, but you are the one checking that the parts mate.
Is there free plumbing design software?
In almost every category: there is free CAD, free sizing tools from valve manufacturers, and our builder — in a browser, nothing to install, no account. There is no free BIM package of design-office grade. The limit is usually not the price but the fact that a free tool does not produce approval documentation.
Can I get by with an Excel sheet and a piece of paper?
For a single branch, easily. The trouble starts at the first change: every altered diameter or reordered part has to be carried by hand through both the drawing and the list — and that is where things get missed.
Does a private house need a hydraulic calculation?
For an ordinary layout with a handful of fixtures, sizing by fixture count and branch length is enough. A full calculation earns its keep when the system is large or unusual: long runs, three floors or more, DHW recirculation, underfloor heating with many loops.
Will a plumber accept a drawing from a builder?
A plumber does not need documentation, they need a clear layout with dimensions and a parts list. That is exactly what a builder gives: the layout is visible, the parts are named and the dimensions are marked, and the question “what did you mean here” hardly ever comes up.