Any diking, drainage, or sewerage improvement district operating under this chapter shall not use concurrently the processes provided for raising revenue for maintenance purposes under any other law: PROVIDED, That any other method of raising such revenue provided by law may be used concurrently for the sole purpose of extinguishing indebtedness incurred before the district adopts the procedures of this chapter, and no funds raised hereunder shall be used to pay such prior indebtedness.
[ 1967 c 184 § 18.]