In the event that the board of water and sewer commissioners of any city ("commissioners") should acquire, operate, or control by virtue of assignment, conveyance, court order, operation of law, or otherwise the water system of a water and fire protection authority ("authority"), then the commissioners shall deposit, in the manner set forth below, the aggregate sum of $8,000,000 into an escrow account to be used for the purpose of constructing improvements which shall supply water service throughout the authority's territory in those areas which do not otherwise have such service. The escrow agent shall be any national banking association with offices located in the city which shall be selected by mutual agreement of the commissioners and the authority. The escrow account shall be funded and utilized as follows: Within six months from the date that the commissioners shall first acquire, operate, or control the authority's water system, the commissioners shall deposit the sum of $2,000,000 into said escrow account. On the same calendar day of such deposit for each of the next succeeding three years thereafter, the commissioners shall deposit the sum of $2,000,000 into said account making the aggregate amount of all deposits into said account $8,000,000. Within the one-year period after each said deposit, the commissioners shall be required to construct improvements for the expansion of water service in areas within the authority's territory which are designated by the governing board of the authority, and as much of the $2,000,000 deposit as may be reasonably practicable shall be used for such construction, and for no other purpose, during each said one-year period. The governing board of the authority shall deliver to the escrow agent and the commissioners at the commencement of each said one-year period a written plan designating the areas within the authority's territory where the improvements shall be constructed during that year. The escrow agent shall be authorized to release funds from the escrow account to the commissioners from time to time during the course of each such year only upon submission by the commissioners to the escrow agent of one or more sworn statements defining the areas where the water service improvements will be constructed and certifying that such areas are included in those designated on the written plan submitted by the authority and that the released funds will be expended within 20 days of release in remittance of the costs of construction of such improvements. The escrow agent shall be entitled to a reasonable fee for its services but not to exceed in the aggregate one-half of one percent of the total amount deposited in said account during the entire period of its existence.