if you mean the ones next to the mabati catholic church near the dam at the gsu tank,then hizo ziko na issues and you should carry out a due diligence exercise,ask why no one has ever been able to build.but the other ones further south near kabogo's place are ok.
hope that helps,and while at beware the land brokers of ruiru.
Every man is guilty of all the good he didn't do-
Voltaire