Cornerstone provided structural engineering services for a pair of replacement water tanks owned and operated by Mid-Peninsula Water District on a geometrically constrained site with residences on both sides and within close proximity to a steep slope at the rear of the site in Belmont. The first phase of the project consisted of a structural, seismic, and conditional assessment of the existing two 30 foot diameter by 20-foot tall steel water tanks that were showing significant corrosion and wear, with some of the internal roof girders being rusted through entirely. Rehabilitation measures were considered against overall replacement from a cost-benefit perspective. The second phase consisted of implementation of the replacement design. The tank site had many irregularities that required earth retaining structures and creative project phasing to complete construction. Demolishing of existing tanks and construction of new tanks was performed from the back of the site to the front. A performance specification was written for the replacement tanks and an external roof framing system was used to maximize capacity of the new tanks and weld efficiency of the roof to rafter interface. The constricted site required that the tank height to width ratios mandated hold-down anchorage and a concrete ring wall foundation.