I'm always suspicious when it comes to government and arithmetic, and the math makes my head spin in the local hand-wringing over federal demands that Honolulu upgrade the Sand Island and Honouliuli sewage plants to secondary treatment.

Mayor Mufi Hannemann cries that it would cost $1.2 billion to comply with what the U.S. Environmental Protection Agency wants, which he says would bankrupt the city on top of the $500 million needed to fix leaky and neglected sewage collection systems in our neighborhoods.

That's where it gets confusing: Why would $1.2 billion on sewers bring bankruptcy, while the same officials insist that it's affordable to spend $5 billion on rail transit — at least $3 billion of which would come from O'ahu taxpayers through the half-cent transit excise tax?

Transit opponents engage in bombast when they deride Hannemann's proposed rail line between Kapolei and Honolulu as the "Train to Nowhere." It's a worthy project that would fill a need.

But it's fair for critics to apply the mayor's oft-stated criteria of nice-to-have vs. need-to-have to transit and sewage treatment.

The rail system would serve only part of O'ahu and is opposed by a large segment of the population, while upgraded sewers would directly benefit the entire island and nearly everybody understands the need.

Hannemann often accuses his predecessor, Jeremy Harris, of paying for glamour projects by deferring needed maintenance and upgrades on basic infrastructure like sewers.

But isn't he engaging in the same kind of deferral by charging ahead with rail while trying to fight off inevitable sewage treatment upgrades?

Hannemann argues that secondary treatment isn't needed because ocean currents sweep away effluent from Sand Island and Honouliuli that is piped 9,000 feet offshore.

But the EPA has produced evidence of troubling bacteria counts, many locals are leery of swimming in waters off O'ahu's south shore and it could eventually affect tourism.

There's no question that upgrades to bring Sand Island and Honouliuli up to national standards will have to be done sooner or later whether the city wins its current battle for waivers or not.

City officials say rail and sewers are separate issues with no connection, but everything is connected when it comes to setting priorities for spending public money.

There's only so much that can be collected in taxes and fees without crushing the economy, and everything must be on the table when we decide which needs are most important.

If $1.2 billion in sewage upgrades would bankrupt the city, it's only because of the transit money being sucked out of the tax base.

Little of the $3 billion being collected locally for rail has been spent, and there's still time to discuss whether it might be a better idea to spend half the money on sewers and half on cheaper traffic solutions.

Putting his pet transit project back in play might inspire the mayor to stop spinning worst-case scenarios on EPA demands and take U.S. Rep. Neil Abercrombie's advice to "start looking at alternatives short of having to spend hundreds of millions of dollars on secondary treatment plants. There are a lot of things short of that which may deal with the problem at hand."

And the state must stop skimming 10 percent off the top of the city transit tax for collection costs that aren't nearly that much. Over the next 20 years, $300 million collected from O'ahu taxpayers supposedly to pay for our essential needs will instead go into a state slush fund.

If Gov. Linda Lingle and the Legislature return this money to O'ahu, it could make a nice down payment for sewer upgrades without affecting any existing program.

David Shapiro, a veteran Hawai'i journalist, can be reached by e-mail at dave@volcanicash.net. Read his daily blog at blogs.honoluluadvertiser.com.

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