If it's a private residential development with no planning requirement for a management company to be set up, then basically you are responsible for grounds maintenance post-completion. The builder couldn't be expected to cut grass etc forever (although some of my old clients had this assumption!)
What I'd be interested in is knowing who pays for the public lighting - the developer or the council? If it's currently the developer & there's no MC provision in the planning, you need to get onto the council quick as, to get them to take responsibility for public services incl. sewage & ESB.