"Most guys spend an average of 55 seconds at the urinal and there's nothing for them to look at apart from our screens, so it's the best exposure for outdoor advertizing," claims Borschberg.

The people who sell space on the side of Shanghai's city buses may, however, beg to differ.

There are also constraints. Certain designer brands are not going to pay to have potential customers urinate over images of their $10,000 handbags, but more adventurous brands may appreciate the potty humor this platform offers.

"You can be super creative with toilet ads," says Borschberg, who also serves as a creative head during the preliminary stages of the campaigns.

"For example, we could run an ad for a pair of shoes and end it with 'What's your size?', which is kind of funny as the guy watching has his pants unzipped."

The 25-year-old Turkish-Swiss, who speaks four languages, has lived in China for three years. He set up Good Media Shanghai early last year and began implementing the "100 Million Campaign" in May 2013.

Growth is exponential: The company had 30 urinals installed by June, but the network has since grown to 100. In the last 18 months, these have saved a cumulative 7.5 million liters of water. The current network can save twice as much in the space of a year.

They need 650 urinals to reach their goal, which they say should happen next summer.