A typical roofscape, as here in Bethlehem, has a set of water tanks and satellite dishes. The water tanks might look familiar to New Yorkers, where they are often found on the roofs of older apartment buildings. Water is stored there to get around the issues of gravity associated with raising water and also offering users water pressure. In Palestine, the issue is simpler: storage. On regular occasions, which I experienced myself during my visit, buildings will be cut off from the water supply by Israel. It is a form of collective punishment, as in the widespread water cuts during Ramadan in 2016 (June-July), following a shooting in a Tel Aviv café.
In order to guard against simply running out of water, the tanks have been installed to collect it when it's on. Palestinians are not permitted to collect rainwater--which must be allowed to run off so Israel controls it--or to drill for groundwater. If this seems unconscionable, compare the cynical actions of the state of Michigan in Flint. The mostly African American population was switched to toxic water from the Flint River for two reasons. It saved some money (in the short term) and by reducing the usage of Detroit's water company, increased the pressure for privatization.
The other main function of the roof is to house satellite dishes. I didn't see any TV myself so I can't report on it. But I did notice that during the European Champions League final, every Palestinian seemed to support Real Madrid. I asked why and it turned out that La Liga--the Spanish football championship--was available free in Palestine so locals had gravitated to supporting Spanish teams. I saw a lot of Ronaldo and Bale jerseys being worn during the constant kickabouts on every patch of vacant land and there were posters advertising the forthcoming European championships everywhere.