Standard&Poor's Ratings Services affirmed its 'BBB' long-term rating and underlying rating (SPUR) on Brazoria County Municipal Utility District (MUD) No. 21, Texas' general obligation bonds outstanding. The outlook is stable. The rating reflects our assessment of the district's: High overall net debt burden, and High direct tax rate, limiting any revenue-raising flexibility. These credit weaknesses are mitigated, in part, by our view of the district's: Mature development, limiting any significant additional capital needs, and Very strong financial position. An unlimited ad valorem tax levied on all taxable property in the district secures the bonds. The 625-acre MUD No. 21 is one of two districts that serve the 1,100-acre master-planned community of the Lakes of Savannah. The district is