What mesh count works best with water-based inks?

In most cases, 200 mesh screens and above will work best with water-based inks. These also allow you to get finer detail out of your images and a softer hand feel on your prints. Thinner inks like water-based need a finer mesh to keep it from seeping through onto the substrate. Many screen printers use 230 mesh when they print water-based inks. Alternatively, you can print up to a 305 mesh, but remember that you’re not going to get as much ink through that screen, so if your artwork is designed to be a little more washed out, you can definitely go higher.

—Texsource Screenprinting Supply