Free AutoCAD water and wastewater treatment symbols (DWG): clarifiers, aeration, filters, membranes

About the conventions

Treatment plant drawings have no single standard symbol set: designers use plan and section outlines that are customary in the industry, and the details differ between countries and companies. Instrument symbols follow the usual circle-and-letter style, as in ISA 5.1.

The blocks are our own drawings, not copies of a standard, and the library is not certified. Check them against the legend of your project or company and change a block if yours differs.

Frequently asked questions

Are the symbols in plan or in section?

Both. Channels, screens, flumes and basins are drawn in plan, and tanks with water levels, filters, clarifiers and digesters are drawn in section, because that is how each is usually shown. Where it matters, the name says which view it is (for example Aeration tank, plan and Aeration tank, section).

Can I use the blocks for a hydraulic profile?

Yes. The section views of weirs, flumes, tanks and filters are suitable for a hydraulic profile, with the water level shown by the wave line. Set the attributes for dimensions and design flow and export the list with BlockSync.

Can I use the symbols in commercial projects?

Yes. They are free to use and modify in your own projects, including commercial ones. They are provided as is, without warranty.

Are the instruments and analysers included?

Yes: pH, ORP, turbidity, dissolved oxygen, conductivity, residual chlorine, TOC and suspended solids analysers, an automatic sampler, electromagnetic and ultrasonic flow meters and an ultrasonic level sensor. The general instrumentation symbols are in the ISA 5.1 library.

Can I change a symbol or add attributes?

Yes. Open the DWG, edit a block with BEDIT to change it or add attributes, and save. To update drawings that already contain the block, run ATTSYNC or replace the block. Make a backup first: attribute values can be lost if ATTSYNC is used carelessly.

Where do I find a ready-made set of these symbols for AutoCAD?

AutoCAD itself ships only a small set of sample blocks, so a full symbol set has to come from a library. Download the ZIP on this page and open the DWG: every symbol is a block. Insert one with INSERT (Blocks palette, Libraries tab, then pick the DWG) or drag it from DesignCenter (ADCENTER). You can also download a single symbol on its own.