LAYTON — City sewer fees will increase by $3 per month, effective July 1, as part of rising costs charged to cities by the North Davis Sewer District.

Because Layton bills residents for two months of water, sewer and garbage service, the fee increase will actually show up on bills as $6 per billing cycle.

The North Davis Sewer District has also approved a $3 per month fee increase every July 1 for the next four years. That means the total sewer fee will have increased by $12 a month, or $24 per billing cycle, by July 1, 2017.

The increases are needed to meet the demands of the growing population and comply with state and federal regulations, city officials said.

The North Davis Sewer District recently updated its facility plan to identify needs of its sewer lines and treatment plant. The plan identified an estimated $167 million in upgrades, expansion, repairs and rehabilitation needs of its facilities.

The district serves about 200,000 people in seven cities and portions of unincorporated areas of Davis and Weber counties. The units that treat the solids contained in sewage were originally constructed in the 1950s and have not been expanded since the early 1980s when the population was less than half what it is now.

The district’s sewer pipes are also aging, and some have been in continuous service for more than 70 years, city officials said.