You could probably coat the hose with a few layers of spray paint that is close to the exterior of your house to help the appearance. You wouldn't need the plastic. The paint will seal the pinholes. The platic also is a dust magnet.

You could also build a box around the exterior hose and paint it to mathc the house. It would not look so odd that way.

With regards to the original question, I would have to say my attempt long ago to use part of a sink for a print washer. I made a plexiglass rig that could set in the sink and had a hole drilled in the bottom so I could insert a tube that acted as an overflow. The tube had several holes drilled to allow water to flow into it at a steady rate after the sink was filled. This way I could keep a constant flow of fresh water going. Well the holes got covered by a print and the top of the tube could not keep up so after I put the prints in and went up stairs you can imagine what i had to deal with 1 hour later.