Lansing is one of the few large cities which obtains its water supply from wells. The wells, 125 in number, are mostly 12 to 14 inches in diameter and 400 feet deep, drilled, for the most part through solid rock. The upper portion of each well is cased with heavy wrought iron or steel alloy pipe driven into bedrock which seals the well from surface waters in the upper gravel and sand deposits.

The Board of Water and Light performs a surveillance survey of the well fields annually, or more frequently if warranted. Analyses are run for chemicals as specified by the National Primary Drinking Water Standerts and for any other chemicals that may be of concern nationally or locally. This testing program is a result of the Board's concern for continual assessment and protection of the aquifer.

The wells are located throughout the service area and furnish the water which is pumped to the two water conditioning plants. Water flows through either the Dye or Wise Plant to receive proper conditioning, which consists primarily of adding lime and soda ash, all of which is later precipitated out along with hardness causing constituents of the raw water; the solfened water is then chlorinated, fluoridated, filtered, and stored in the resevoirs prior to distribution.

The Board of Water and Light obtains samples of the well water feeds and finished water at the conditioning plants on a monthly basis as a surveillance function for any chemical combination. Additionally the water in the distribution system is analyzed annually for chemical compliance with the National Dronking Water Standarts.

When the water from the wells first enters the water conditioning plants, 80 percent of it flows through several large concrete mixing basins (primary basins) where lime, in the right quantity, is mixed with the water. This gives the water a milky white appearance, party due to the lime that was added and partly due to the fact that when lime is added to a hard water, dissolved calcium and magnesium minerals plus any carbon dioxide come out of solution in the form of minute, white calcium carbonate and magnesium hydroxide flakes which can later be removed. The mixing basins have large paddle wheels turning in them so the white flakes form throughout all of the water and become as large as possible. the formation of the flakes, or floc, is really the softening process.

Next, the floc is allowed to settle out of the water. Large, deep, quiet flowing basins lying underneath the primary mixing basins, let the water flow with so little disturbance that most of the white floc settles out of the water and is drained off as a milky slurry. This is pumped to a filter press for end uses outside the system, such as spreading on agricultural lands, or for land reclamation.

While most of the lime first added has settled out of the water in the form of carbonates at this point, some still remains that was not used in the conditioning process and this still is not in flake form. To convert this lime to a flake form for easy removal, the water enters a second series of mixing and settlig basins (secondary basins) where soda ash, raw water (20 percent of the total influent) and secondary basin slurry are added. Because lime reacts with only the calcium and magnesium bicarbonate minerals, other dissolved calcium and magnesium hardness forming compounds in the well water must be removed by mixing soda ash with the water in the secondary set of basins. The raw water that is added eleminates the excess lime carried over from the primary basins while the amount of secondary basin slurry that is recycled aids in the formation of additional floc in these basins. When the water leaves the secondary set of settling basins, it flows to the final settling basins for additional clarification prior to being conveyed through the pipe galleries to the filters.

In filtering, the water passes through about four feet of graded sand and gravel. It leaves the filters crystal clear. After the filters have been used about three days they become partly clogged with fine floc particles, so they must be cleaned. This is done by reversing the flow of water through the filter, bringing the water in at the bottom of the filter and taking it off the top. To do a good cleaning job the water must flow in the reverse direction a lot faster than it does when it os being filtered. To avoid lowering the pressure in the water mains, the wash water is taken, for example, at the Dye Water Conditioning Plant, from a 110,000 gallon tank in the high portion of the building at a very rapid rate. The wash water is not wasted but is again passed through the plant and cleaned.

After the water has been filtered it then flows to the large near-by underground reservoirs which hold about a day's supply. From the reservoirs it is pumped by means of electric-driven pumps into the water mains that distribute it to all parts of the service territory.

The average daily pumpage of water is currently 17,000,000 gallons; the current maximum daily pumpage is 39,600,000 gallons. For periods of a few hours during the summer months water is sometimes used at rate greater than 35,000 gallons per minute.

The Dye Conditioning Plant was designed for a maximum output of 40,000,000 gallons per day with eight filters equipped and in use. Provisions have been made for four additional filters.

The Wise Water Conditioning Plant is presently capable of producing 10,000,000 gallons per day with four filters. Provisions have been made to allow this plant to produce at 20,000,000 gallons per day, if emergencies necessitate it.