The Morro Bay City Council and Cayucos Sanitary District Board have all but abandoned an ill-conceived plan to build a new sewer plant on a flood plain.

Good for them. It shows strong leadership to stop wasting time and public money trying to defend an indefensible project. We only wish the about-face could have occurred before hundreds of thousands of dollars were spent on a doomed project — including nearly $150,000 that went to a consultant hired to lobby for the project — but it took the election of a new City Council majority in Morro Bay to turn the tide.

Now that both Morro Bay and Cayucos have withdrawn their support, the Coastal Commission should deny the project when it meets today in Pismo Beach.

As the Coastal Commission staff report points out, there are several problems associated with the proposal to build a new sewer plant at the same coastal location as the existing one:

• The use is not permitted under the city’s Local Coastal Program (the existing plant had to be “grandfathered in”).

• The site is in a flood plain and a tsunami zone.

• It’s a poor use of valuable coastal property that could otherwise be dedicated to visitor-serving uses such as bike trails and walkways.

• Most of the plant’s treated wastewater would be discharged into the ocean, which is a waste of a precious resource — especially in drought-prone California.

As we’ve noted previously, cost savings is the one big advantage to the old site. Moving the plant to a new location could cost an additional $12 million, though the Coastal Commission report points out that grant funding could defray that cost.

Besides, cutting costs — as tempting as that is — could backfire in the long run, especially if a flood-induced sewage spill were to occur.

Bottom line: It makes no sense to continue pouring money into a project that has little, if any, likelihood of ever being permitted by the Coastal Commission.

We agree with the Morro Bay City Council and Cayucos Sanitary District Board: It’s time to move on.