The water in your homes comes purely from delsalinated water, there is no RO units working in Qatar at this time, the water from these plants is completely safe to drink, it is distilled from seawater and reminralised at the plant, treated with a small amount of chlorine to keep bugs from growing and sent to Doha.

As Doha has only enough resevopirs in summer for about 3 days supply it comes to you very quickly, the only issue of quality maybe is from old lines (not very probable) or from your own tanks (most probable), just check them out, a small film of brown in the bottom is only fine dust, anything else maybe a problem, make sure the top fits snuggly and you will be ok to drink it, dependant on area it can be recommedned to use a standard filter to remove sediments.

To use a samll RO unit in this country is just not required and if you get the balance wrong can be dangerous.

As mentioned before all bottled water made in Qatar is just blended ditileed watter with extra minerals added to enhance the taste, but not required

Hope this helps