Atascadero residents could soon see their sewage bills go up after the state mandated the city undertake a costly plan to upgrade its water treatment plant. To help fund the project — currently expected to cost upwards of $173 million — the city is considering a sewage service rate increase of 18.5% to go into effect this year, followed by a potential increase of the same amount again in 2026. A single-family household would pay over $100 more every year, according to the staff report from the April 22 city council meeting. But there is still a chance the rate increase might fail. … If a majority of impacted homeowners or lease holders protest the rate increase, Atascadero would be legally blocked from imposing the fee.