When WSB broke the story July 13 about hundreds of leaks in the waterproofing “membranes” atop the new concrete covers at Myrtle Reservoir in West Seattle and Beacon Hill Reservoir, Seattle Public Utilities told us they had not yet calculated the cost of redoing those membranes. They stressed that they expect the cost eventually will be someone else’s responsibility – depending on where the fault is found to lie – but in the meantime, the city has to front the money to get the work redone. The faulty membranes are being removed now, and a “hot asphalt” process will be used instead. SPU’s Andy Ryan has just sent us the information on the costs, as he had promised they would do as soon as “change orders” were complete:

We now have an estimate on the cost of removing and replacing the waterproof membranes at the Beacon and Myrtle reservoirs — about $4.1 million.

As you reported last week, once liability for the waterproofing problem has been established, Seattle Public Utilities will be seeking recovery of costs from our vendors.

We have not yet established the cause of the breaches in the waterproofing material, nor have we fixed responsibility for the problem. As we told you last week, that determination will likely be part of a lengthy legal discussion between SPU, the project designer and the contractor. To reiterate what we said last week, we do not believe SPU is responsible for any of these problems.

Overall, Seattle’s $150 million reservoir covering program is about $15 million under budget.

Please allow us to emphasize, again, that the water in the reservoirs is safe. We have a comprehensive water quality testing program, regulated by Washington State Department of Health, that confirms that there are no water quality impacts from the waterproofing problem. In fact, at Beacon and Myrtle the water is much better protected, and the water quality even higher, than in Seattle’s old, uncovered reservoirs. The state Department of Health is fully informed of these issues and believes our water is safe.

Construction work on the Beacon and Myrtle Reservoirs is expected to be completed by the end of November. Until the work is completed, the two reservoirs will remain fenced off, as has been the case with our open reservoirs.

Our first priority is getting the waterproofing done right on these projects, which will be serving Seattleites — as reservoirs and parks — for at least the next 100 years.

Our original story on the waterproofing leaks stemmed from neighbors’ e-mails to WSB, asking why the project – which they had thought to be complete – “was being dug up again.” (We also published a followup later in the week.) Earlier this week, we asked SPU why we hadn’t seen activity at the site for several days; Ryan and reservoir project manager Stephanie Murphy explained that the crews are removing the membrane material at Beacon right now and scheduled to resume work at Myrtle in early August.