Mixed-use and market-rate multifamily projects are technically dense. You’re stacking occupancy types, coordinating multiple utility meters in a single structure, designing drainage for an above-grade concrete deck, and threading fire apparatus access around a building that covers most of the site. Each of those problems has a specific engineering answer, and getting any one of them wrong shows up in entitlements, permits, or construction costs.
Calichi Design Group has worked through these problems on real projects. On a 57-unit mixed-use affordable housing complex at 95th and International Boulevard in Oakland, we produced civil entitlement documents with feasibility study, full construction documents, and secured both City of Oakland and Caltrans encroachment permits for a project whose boundary touched State Route infrastructure. That kind of layered permit coordination is typical for mixed-use infill, and it’s what we expect from the start, not discover at submittal.
We’re a civil and stormwater engineering firm with offices in Oakland CA, Portland OR, Hood River OR, and Maui HI. We hold PE licensure across 42 states and have completed civil work on mixed-use and multifamily projects in California, Oregon, Hawaii, Arizona, Ohio, and other markets. All projects come with a fixed-fee proposal so your civil budget is known before design starts.
Why Mixed-Use and Multifamily Civil Engineering Is Different
Most civil engineering projects have one occupancy type, one utility service point, and a building footprint that stays well clear of the site boundary. A five-story podium building with 120 residential units above retail doesn’t work that way. The site coverage is high, the utility load is large, the building type creates drainage surfaces at multiple elevations, and the fire access perimeter requirement can wrap the entire structure. None of those problems is unsolvable, but each one requires deliberate engineering from early in schematic design, not as a permit comment response.
The civil discipline touches every other design discipline on these projects. The structural engineer needs drain penetration locations before the podium deck is detailed. The architect needs the fire access lane geometry before the site plan is frozen. The mechanical engineer needs the gas service size and routing path before the utility room is located. Our job is to get ahead of those coordination points and resolve them before they become conflicts.
Civil Engineering Services for This Sector
- Site civil engineering: grading, drainage, paving, ADA path of travel, utility laterals, encroachment permits, and full construction document sets for building department and public works review
- Stormwater management: C.3 and hydromodification sizing, stormwater control measure design, LID feasibility on constrained infill sites, and Operation and Maintenance Agreements
- Fire flow studies: fire flow testing, hydraulic analysis, water main adequacy documentation, and coordination with the local water purveyor when existing infrastructure is undersized
- Dry utility consulting: joint trench design, franchise utility coordination (electric, gas, telecom), transformer and vault location, meter room planning, and permit submittals to each utility provider
- Podium drainage design: above-grade deck drainage, slope-to-drain layout, emergency overflow routing, and coordination with the structural and waterproofing team
- Entitlement civil: feasibility studies, civil constraints analysis, and agency pre-application coordination to identify site-specific requirements before design dollars are committed
Podium Drainage: Above-Grade Civil Engineering
A podium building puts a concrete or post-tensioned deck above structured parking or ground-floor commercial space and stacks wood-frame or steel residential construction on top. From a civil standpoint, that deck is a drainage surface as well as a structural element, and it has to be engineered as both.
Drainage for a podium building operates at three levels simultaneously. The residential floors above generate roof drainage that comes down through the building’s internal drain system. The podium deck itself collects surface water from amenity areas, pool decks, planters, drive aisles, and landscaped setbacks. The base-level grade around the perimeter of the building collects runoff from whatever site area isn’t covered by the structure. Each level needs its own collection system, and all three have to converge on connection points that work with the storm drain infrastructure on or adjacent to the site.
The coordination challenge is that drain penetrations through the podium slab are structural commitments. Once the post-tensioned deck is cast, moving a drain location means cutting through prestressed concrete, which no structural engineer will approve after the fact. Civil drainage design for a podium has to be coordinated with the structural engineer before the slab is detailed, and the drain locations in the civil plan have to match the structural drawings exactly.
Waterproofing coordination matters too. A podium deck that doesn’t drain positively to its drains will pond water, and ponded water on a waterproofed deck is a long-term envelope failure. We design drainage slopes and outlet locations to move water to collection points quickly, and we make sure every primary drain has a designated emergency overflow path that routes excess water to a place it won’t damage the building or adjacent property.
On projects where the podium sits close to an existing public storm drain system, we verify available invert elevations and confirm the public infrastructure can accept design flows without surcharging during a design storm. That’s a site-specific hydraulic calculation, not an assumption. On projects with green roofs or planted decks at the podium level, we account for the drainage mat system, retention layer, and altered flow rates when sizing the primary drain system.
Joint Trench for Multi-Meter Buildings
A single-family home gets one electric service, one gas meter, and one conduit path for telecom. A 100-unit mixed-use building gets a master electric service sized for the whole building, individual residential meters for each unit, a separate commercial service for retail, a gas service sized for the building’s mechanical load, and conduit sleeves for multiple telecom providers. All of it runs underground from the street or transformer vault to the building, and all of it has to be coordinated in a single plan.
Joint trench puts multiple utility services in one excavated path, with each utility at its required depth and horizontal separation from the others. It’s standard practice on large multifamily projects because opening the ground once is less expensive and disruptive than having each utility trench separately. But getting to a single trench requires the civil engineer to coordinate all utilities on a shared schedule, and those utilities don’t naturally talk to each other.
PG&E, SCE, SoCalGas, Southwest Gas, NW Natural, and local municipal utilities each have their own service agreement process, design submittal requirements, and review timeline. Telecom providers, including AT&T, Comcast, Frontier, and local fiber operators, have separate conduit installation standards and in many cases separate permit requirements. The civil engineer’s job is to get all of those moving at the same time so the trench happens once.
For a large multifamily building, the transformer vault location, switch gear room, and meter room are architectural and structural commitments. If those locations change after the civil utility plan is drawn, the trench route changes, and in some cases the encroachment permit needs to be revised. We build the joint trench plan around committed architectural information and flag any design decision that would force a re-route before it becomes one.
Our dry utility consulting services include joint trench design, franchise utility coordination, conduit counts for all providers, permit submittals, and construction-phase coordination with utility inspectors. For a building of 60 units or more, we recommend including dry utility coordination in the civil scope at the start of schematic design, not at construction documents.
Fire Apparatus Access Around Podium Buildings
Fire access is one of the first civil constraints on a podium building site plan, and it’s one of the most frequently left until too late in schematic design.
Under California Fire Code Section 503.1.1, a fire apparatus access road must extend to within 150 feet of all portions of the first-story exterior wall. On a building that covers most of the parcel, that 150-foot coverage requirement can force fire access on sides of the building where the project had planned landscaping, parking, or a pedestrian amenity. The site plan has to accommodate the fire lane before the architect freezes it, not after.
CFC Section 503.2.1 sets a minimum fire lane width of 20 feet, exclusive of shoulders. That’s the floor, not the design standard. Many fire marshals require 24 or 26 feet for ladder truck access to residential buildings taller than three stories. The specific turning radius is determined by the fire code official under CFC Section 503.2.4 based on the jurisdiction’s apparatus, so it needs to be confirmed in a pre-application meeting with the fire marshal, not assumed from a generic value.
Dead-end fire apparatus access roads longer than 150 feet require an approved turnaround area under CFC Section 503.2.5. On a tight urban infill site, fitting a hammerhead or cul-de-sac turnaround while meeting setbacks and maintaining required parking counts is a constraint management problem. We work through that geometry at schematic design so the architect knows what the site can and can’t absorb before committing to a layout.
Fire flow is a parallel requirement. Most AHJs require documented fire flow at the nearest hydrant serving the project before issuing a building permit. For a 150-unit residential building, required fire flow can exceed 3,500 gallons per minute at 20 psi residual depending on the jurisdiction and building type. Our fire flow study services include the field test, the hydraulic analysis, and coordination with the local water purveyor if the existing main can’t deliver the required flow at the project’s design condition.
In Portland, fire apparatus access requirements come from the Oregon Fire Code and Portland Fire and Rescue’s own design standards. Requirements differ from California’s CFC in specific ways, and we work with both fire bureaus regularly. The principle is the same in both markets: confirm the access geometry early, confirm the turning template with the fire marshal’s office, and get the fire lane into the site plan before the structural grid is locked.
Stormwater Management on Tight Infill Sites
Mixed-use and multifamily infill projects typically increase impervious cover over whatever was on the site before. In the San Francisco Bay Area, projects creating or replacing more than 10,000 square feet of impervious surface trigger post-construction stormwater requirements under the Municipal Regional Stormwater Permit (MRP 3.0), which is administered through local municipalities with programs such as Alameda County’s C.3 requirements. Those requirements call for stormwater control measures sized to treat the design storm runoff from all new and replaced impervious area. Projects above a higher threshold also face hydromodification management requirements, which regulate peak flow rates and not just water quality.
On a site where the podium covers 65 percent of the parcel and amenity areas cover another 20 percent, there isn’t much room for conventional bioretention cells or flow-through planters at grade. That’s where the civil engineer’s role is to find what treatment can actually fit: a ground-level planter strip along the street frontage, a vault-based proprietary media filter under the plaza, or a structural soil tree trench in the public right-of-way if the local public works department allows it. We do the LID feasibility analysis before recommending a treatment type so we’re not designing a facility that won’t fit.
Our stormwater management services for multifamily projects include C.3 and hydromodification sizing, stormwater control measure design and specification, LID feasibility analysis for sites with limited available area, Operation and Maintenance Agreement drafting, and coordination with the local stormwater authority through plan check and approval.
In Oregon, stormwater requirements come through the Oregon DEQ and local MS4 permit conditions rather than the California MRP structure, but the technical challenge is the same: fit meaningful water quality treatment into a dense infill site plan that doesn’t have much ground to give.
Entitlement, Permits, and Agency Coordination
For a mixed-use or multifamily project, the civil engineering permit set typically includes grading and drainage plans for the building department and public works, joint trench or underground utility plans coordinated with each franchise utility, fire access plans approved by the fire marshal or fire bureau, a stormwater control plan for the local stormwater authority, street improvement and sidewalk plans for the right-of-way, and in many jurisdictions a separate hydrology report. Each plan set goes to a different agency on a different timeline.
The critical permit path often runs through fire access and stormwater, because both of those generate rounds of back-and-forth with the reviewing agency before approval. Knowing which comments to expect, and how to structure the response, shortens that cycle. We write the plan check responses, not just the plans.
Jurisdictions and Agencies We Work With
For mixed-use and multifamily projects, our most frequent agency and utility relationships include:
- City of Oakland Bureau of Building, Oakland Public Works, and Oakland Fire Department
- City of Portland Bureau of Development Services, Portland Fire and Rescue, and Portland Bureau of Environmental Services
- Alameda County Clean Water Program (C.3 and MRP 3.0)
- EBMUD (water and sanitary service, Bay Area)
- PG&E and SCE (electric service and joint trench coordination)
- SoCalGas, Southwest Gas, and NW Natural (gas service coordination)
- Caltrans (encroachment permits for sites adjacent to state right-of-way)
- Honolulu Department of Planning and Permitting
- Arizona and Ohio municipalities served by our licensed remote PEs
Representative Projects
57-Unit Affordable Housing Complex, Oakland, CA (95th and International Boulevard): Civil entitlement documents with feasibility study, full construction documents, and City of Oakland and Caltrans encroachment permits for a mixed-use 57-unit affordable housing project. Coordinating Caltrans and City permit review timelines for the same site condition requires managing two separate sets of design standards and two independent plan check processes running in parallel.
KIPP Bridge Academy, Oakland, CA: Civil design for a two-story school on a constrained urban site including grading, storm drainage, stormwater control measures, and utility coordination. The approach to stormwater treatment within a tight footprint on this project informs how we handle mixed-use infill where available area for treatment facilities is limited.
Dublin Transit Center, Dublin, CA: New construction of a five-story, 516-space parking structure on a 2.5-acre parcel. Above-grade drainage coordination on a structured parking facility follows the same principles as podium drainage on a multifamily building: coordinating deck drainage slopes, drain penetration locations, overflow paths, and connections to the public storm drain system.
Frequently Asked Questions
What is a podium building and what specific civil engineering does it require?
A podium building uses a concrete or post-tensioned structure at grade for parking or commercial space, with wood-frame or light-gauge steel residential construction above. The civil engineering requirements specific to a podium include above-grade deck drainage coordinated with the structural engineer and waterproofing consultant, fire apparatus access meeting the AHJ’s perimeter coverage requirements, joint trench routing for multiple utility services entering the building from the street, and stormwater management for the building’s impervious surfaces at multiple elevations.
How do you design fire access when the building covers most of the site?
This is a site plan geometry problem that has to be solved at schematic design. We run the CFC 503 access requirements against the proposed building footprint early and identify any side of the building that can’t meet the 150-foot coverage distance without a dedicated fire lane. Then we work with the architect and fire marshal to lay out a fire access route that threads through the site without eliminating required parking, ADA routes, or required landscaping. On small urban sites, this sometimes requires an AHJ pre-application meeting before the site plan is finalized, so that the fire marshal’s turning template and lane width requirement are known inputs, not surprises at permit submittal.
What stormwater requirements apply to a 120-unit mixed-use building in the Bay Area?
In most Bay Area jurisdictions operating under the Municipal Regional Stormwater Permit (MRP 3.0), a project creating or replacing more than 10,000 square feet of impervious surface triggers C.3 post-construction stormwater requirements. For a building of that size, the project will almost certainly exceed that threshold. That means sizing stormwater control measures to treat the design storm runoff from all new and replaced impervious area. Projects over a higher threshold also trigger hydromodification management requirements addressing peak flow rates. The specific thresholds and applicable permit provisions depend on the municipality. We confirm the applicable requirements at the start of the civil scope and design the treatment facilities to meet them.
How does joint trench work for a building with 100 individual utility meters?
Joint trench puts electric, gas, and telecom services in a single excavated path with each utility at its required depth and separation. For a 100-unit building, the electric service has to be sized for the combined residential and commercial load, and the trench path has to accommodate a transformer vault or equipment room at the building. Each utility has a separate service agreement process and submittal package. We run those processes in parallel so the trench can be excavated once. The key is locking the transformer location, meter room location, and building entry point early enough that the trench route doesn’t need to change after permits are issued.
Do mixed-use and multifamily projects typically need encroachment permits?
Yes, in most jurisdictions. Any work in the public right-of-way, including curb cuts, sidewalk improvements, street tree wells, utility lateral tie-ins, and street light or traffic signal modifications, requires an encroachment permit from the local public works department. If the project site is adjacent to a state highway or state right-of-way, a Caltrans encroachment permit is also required, with its own design standards and review timeline. We handle both as part of the standard civil scope and flag the Caltrans requirement at the start of the project if the site conditions indicate it applies.
What states does Calichi work in for this building type?
We hold PE licensure across 42 states and have completed or are active on mixed-use and multifamily civil work in California, Oregon, Hawaii, Arizona, and Ohio, among other markets. Our Oakland and Portland offices carry most of the West Coast volume. Projects in other markets are staffed by licensed remote PEs who work from local code and coordinate with local AHJs directly. Fixed-fee proposals are available regardless of location.
When should we bring a civil engineer into a multifamily project?
Earlier than most development teams do. The fire access geometry, stormwater treatment area requirement, and utility coordination timelines all affect the site plan before the architect freezes it. If you’re in predevelopment or early schematic design, a civil feasibility review is the fastest way to find out whether the site can accommodate the building you’re planning or whether a constraint will force a design change. We offer feasibility-level scopes with fixed fees so there’s no ambiguity about what you’re paying for.
Start Your Project
Tell us where the site is, what you’re building, and where you are in the process. We’ll send you a fixed-fee civil engineering proposal within five business days and flag any site-specific constraints we can identify from available information. Mixed-use and multifamily projects are most cost-effective to engineer when the civil scope starts at schematic design. The later the civil team comes in, the more of those constraints get discovered as conflicts instead of inputs.
Contact Calichi Design Group to discuss your mixed-use or multifamily civil engineering project.