Southwest Boise can now get on city sewer. Is it enough to bring in businesses?

Residents and businesses in unincorporated Southwest Boise can now connect to the city’s sewer system — if they’re willing to pay.

The Boise City Council on Tuesday officially ended a 12-year-old moratorium blocking buildings southwest of the city limits from connecting to sewer lines. The catch: Future customers will have to pay for the hookup — likely a six-figure bill — and agree to support annexation into the city at a future date, should a vote come up.

Southwest Boise advocates, though, hope that allowing structures to hook into the central sewer system will spur more commercial development in the highly populated — and overwhelmingly residential — corner of Ada County that abuts Boise’s border.

That sort of construction has stalled since the prohibition on new sewer hookups outside the city took effect in 2014, according to Marisa Keith, president of the Southwest Ada County Alliance. Instead, “we got a lot of low-density single-family homes,” Keith said in an interview with the Idaho Statesman — the precise sort of growth that the housing-conscious Boise City Council is loath to promote.

“It’s a lot of housetops,” Keith said, “and no businesses that would need that sewer.”

Keith doesn’t expect existing residents to jump at the chance to join the sewer district, though she’s optimistic it will sway the owners of properties waffling between commercial and residential options, allowing new types of businesses to open. For more than a decade, reliance on septic tanks has handcuffed the type of businesses that could come to Southwest.

Council Member Colin Nash talked during a Jan. 27 work session on sewers about an auto parts store using a septic tank. Keith mentioned a Dutch Bros coffee shop running on one, too, as well as other businesses — a restaurant and hair salon — that abandoned plans for the neighborhood after learning the peculiarities of its sewers.

Council members want to see businesses in Southwest, too. They just have few levers to influence the area, which exists in limbo between urban Boise and rural Ada County.

Boise’s city sewer, which isn’t bound to the municipal limits, is one way to do that. The system already provides service to parts of Garden City, Eagle and unincorporated Ada County, including some areas of Southwest Boise. It operates like a utility — or, as Council Member Luci Willits called it, a “pay-to-flush system”: Sewer costs are covered by ratepaying users, regardless of the jurisdiction in which they live.

“This is something that I know has been talked about for a long time,” City Council Pro Tem Kathy Corless said during a Jan. 27 city work session on sewers. “We’ve seen a lot of aggressive growth out in Southwest Boise, but the commercial side has been really hindered, and that’s in large part due to what we have in place today.”

Sewer hookups a costly proposition

The change is the latest reversal for an unincorporated neighborhood that has confounded city and county planners since it burst from farmland some 50 years ago. Issues date back to the 1970s, when booming subdivisions compromised water quality, prompting Ada County to halt development

Today, Southwest Boise has densely populated areas that depend on systems typically meant for rural communities. Most homes use septic fields and nearly all rely on wells, according to Jim Pardy, Boise’s city engineer.

In isolation, those systems work well, Pardy said. But as of 2020, nearly 50,000 people lived the neighborhoods that Pardy’s plan would bring into the fold, a chunk of land roughly bounded by Victory Road to the north, the New York Canal to the south, Cloverdale Road to the west and Cole Road to the east.

“When you have high densities of septic and individual wells, that’s when you see a problem,” Pardy told the council members on Jan. 27.

In the 1970s — and, to some extent, today — the issue was nitrates in water. Today, about half of Southwest Boise falls in the Idaho Department of Environmental Quality’s Ada Canyon Nitrate Priority Area and is subject to extensive groundwater monitoring. The most recent DEQ data shows that nitrates were within safe limits in all but one well in Southwest Boise.

More pressing, Pardy said, are the septic systems and their accompanying drain fields. Septic systems don’t last forever, and the fields into which they release treated water can lose effectiveness or become overwhelmed. (That’s why the DEQ requires homeowners to set aside space for a second field on their lots.)

“There are a large number of subdivisions out there that are on individual septic, and those will fail at some time,” Pardy told the council members. “Then, they’ll either have to pay for expensive treatments, or they have to come onto the sewer.”

Hooking into the sewer system is expensive, too. Pardy estimates that 1,000 feet of line — the length the sewer district will install for free to prepaid customers within city limits — costs upward of $300,000 to install.

The district also reserves the right to deny a hookup by requiring that new customers receive a “will serve” letter from the city agreeing to take up the customers. Pardy said that consideration is to restrict water-intensive operations from overwhelming the pipes — “so we don’t get a bunch of data centers out there,” as he put it.

With the price in mind, converting existing septic systems to sewer will be slow, Pardy said. Keith agreed, saying that the cost “is more money than what most people can spend.”

“I don’t think this will solve [a septic system problem] for most people.”

Annexation still unlikely for Southwest Boise

The new policy seems unlikely to speed the annexation of Southwest Boise into the city proper.

Keith told the Idaho Statesman that she “was not confident” there was interest on either side to make it happen, adding that her neighborhood association wasn’t contacted by the City Council to talk about the amended sewer plan.

Pardy, too, made it clear that the consent-to-annexation clause, which was already standard before the moratorium, was added to preserve the option — someday.

“If we give it up now, we’re not getting it back,” he said. “Everyone wants the sewer. Not everyone wants to be annexed.”

Still, the council unanimously supported the lifting of the moratorium in a Jan. 27 work session and again on Feb. 3.

“My view is that it’s about damn time,” Willits said.