(a) This subchapter shall not apply to any municipal improvement district which operates a water system, a sewerage system, or an electric light or power system; nor to any district whose commissioners are elected by property owners; nor to any district which is repairing streets, sidewalks, or other improvements from the proceeds of redemptions or sales of lands forfeited to it under previously existing laws.
(b) This subchapter shall not apply to any municipal wharf improvement district or municipal paving improvement district which is entitled to, is eligible for, and can qualify for state aid and has not received any or all thereof.