My goal was to create a cat water fountain with a carbon filter which can be left unattended for a few days when you are on a trip. We have a commercial one, but a power outage would leave the cat without access to water. For this purpose I designed the white fountain, which is mounted on a bowl. It has an inexpensive water pump and a carbon filter, so the water is circulating and filtered either on continuous mode or on intermittence mode using a timer socket. Pets always have access to drinking water even if the pump is not running.

I also made a conventional cat fountain using the same design (blue fountain). This model may be more complicated, since getting 3d-printed parts watertight can be challenging. If you are interested on this topic, take a look at https://www.thingiverse.com/thing:4921885 and the tips below. Note that this fountain cannot be used if the pump is not working.

To test these models I printed them in PLA+, but for a continuous use PETG would be better because PLA shows poor long-term water resistance.*

Prints are straight: no supports or rafts are required. Pieces fit together without glue.
Working fountains: https://youtu.be/fT9rXM3BbvY

*Note: after 2 months of use PLA+ shows good water resistance.

MATERIALS
In addition to the included 3D printed pieces you would need:

• A USB mini water pump:
  http://tiny.cc/su8juz http://tiny.cc/l66iuz
• For simplicity, I use commercial filters: HoneyGuaridan W25/W18 Pet Water Fountain Replacement Carbon Filters.
  http://tiny.cc/266iuz http://tiny.cc/qs7iuz
• A DC power supply in the range of 5v DC. An old cell phone charger would fit.

TIPS

Some general tips to achieve watertightness for the lower part of the blue fountain:
-PETG Filament
-Do not use supports
-Layer height/resolution: 0.2mm
-Extrusion width: 0.45mm (for 0.4mm nozzle)
-Avoid infill, solid base and perimeter work best