Concerning water treatment or recycling, you must first determine how much capital you are willing to invest, as solutions can range in price from less than $10,000 to $100,000 and more. The answer ranges from “some recycling” (with a permitted discharge for use of city water for critical applications), or a totally closed loop, zero-discharge system that requires no permitted discharge.
All fabrication equipment requires varied levels of water clarity. For a bridge saw, all that is needed is cooling water - “gray water” is usually acceptable. The same is generally true for the cooling ring or halo of a CNC. But a waterjet, the spindle of a CNC and most polishing equipment (including hand polishers) require a much higher water quality specification. Often, people use city water for these applications, although acceptable recycling solutions are available that do not require you to discharge excess water. Flow rates and pressure requirements for your equipment are key pieces of information that you will need to know as well.