Most Lawrence taxpayers probably aren’t surprised that an audit presented to Lawrence city commissioners this week showed a sizable increase in city spending.

The audit showed that the city’s general expenses had increased by about $4.5 million last year. At the same time the city balance sheet, which measures city assets against expenses, grew at its slowest rate since 2004. While benchmark cities saw their assets grow by about 4 percent in 2013, Lawrence’s assets grew by less than 2 percent.

City Auditor Michael Eglinski attributed part of that downturn to the loss of federal stimulus money, but it seems that most of the benchmark cities would have faced a similar loss. It seems, therefore, that Lawrence is having more trouble than other cities in producing enough revenue to keep up with its growing expenses.

For instance, the city has invested significantly in its water and sewer infrastructure in recent years, and revenues have not kept pace. In 2013, the city had $7.06 million in net sewer and water revenue and had to pay $5.27 million on bonds. The year before, the city had $4.5 million in debt and $8.6 million in net revenue, providing a significantly larger cushion. A relatively wet summer last year reduced water demand and, consequently city revenues, Eglinski said.

It’s hard to argue with spending money on infrastructure improvements to support a core city service, especially when those improvements are financed directly from user fees. This situation warrants monitoring, but as long as the city doesn’t have to dip into other funds to make up shortfalls in water and sewer revenue, maintaining infrastructure is a good investment.

However, in recent years, the city has committed to a number of projects — its new library, a new recreation center, a new director of arts and culture — that will have a long-term impact on city expenses. In addition to that, the city has ongoing expenses, some of which may have been pushed back to make room for spending on special projects. For instance, City Manager David Corliss noted that replacement of aging city vehicles and equipment may be a significant budget item next year.

The bottom line of this audit confirms that Lawrence’s city tax revenue currently isn’t keeping up with its growing desire for new facilities and initiatives. It’s a warning flag that likely will be the topic of considerable discussion in next year’s City Commission election campaign.