We provide complete stormwater management and drainage engineering for residential and commercial properties throughout Washington. Our licensed engineers ensure code compliance and effective water management.
Comprehensive Stormwater Drainage Solutions
Site Drainage Analysis
Comprehensive analysis of runoff patterns, flow rates, and drainage requirements. We evaluate site topography and soil conditions to design effective drainage solutions that protect your property.
Stormwater Management Plans
Complete stormwater management plans including calculations, routing, and BMP (Best Management Practices) design. Ensures compliance with local and state regulations for water quality and runoff control.
Catch Basin & Inlet Design
Strategic placement and sizing of catch basins, area drains, and inlets to efficiently collect surface water and prevent flooding on your property.
Underground Drainage Systems
Design of underground storm drain pipes, French drains, and subsurface drainage systems to effectively manage and route stormwater away from structures and critical areas.
LID & Bioretention Design
Low Impact Development (LID) solutions including bioswales, rain gardens, permeable paving, and infiltration systems that meet Washington stormwater requirements and reduce runoff.
Erosion Control Plans
Engineering design for erosion and sediment control to protect your site during and after construction. Meets SWPPP requirements and local jurisdiction standards.
Same-day quote • 2-3 weeks delivery • No hidden fees
Don't Have Plans or Architectural Drawings Yet?
No problem! We work with a network of trusted, design partners and licensed architects who can help you design your project from scratch. Once your design plans are ready, we'll handle all the structural engineering seamlessly.
What Our Clients Are Saying
See why homeowners and industry professionals across Washington trust us with their projects.
Trusted by developers and homeowners across Washington
Fast delivery • Permit guarantee* • Fixed Transparent Pricing
Built for Speed, Clarity, and Permit Success
Why Clients Choose ProStruct Engineering
2-3 Week Express Delivery
Don't wait months for drainage plans. We deliver complete, permit-ready stormwater plans in just 2-3 weeks so you can move forward with your project quickly.
Permit Revision Guarantee*
If building departments have comments related to our scope of work*, we'll revise plans at no extra charge--no matter how many rounds it takes. We stand by our work until your permit is approved.
Licensed Washington Civil Engineers
All our engineers are Washington licensed Professional Engineers (PE) with expertise in stormwater management, drainage design, and Washington building codes and regulations.
Statewide Washington Expertise
We serve all of Washington from Seattle to Spokane, Tacoma to Vancouver. Our engineers are familiar with local jurisdictions, regional requirements, and Washington stormwater regulations.
Your Own Dedicated Project Manager
Every project includes a dedicated project manager at no additional cost. They coordinate with our engineers and collaborate with architects and contractors to ensure clear communication and seamless project delivery.
Transparent, Fixed Pricing
No hidden fees or surprises. We provide detailed quotes upfront so you know exactly what to expect. Competitive pricing with exceptional quality and service.
Serving All of Washington
We're trusted civil engineers providing stormwater drainage solutions for property owners and AEC professionals throughout Washington. Serving Seattle, Bellevue, Tacoma, Spokane, Vancouver, Olympia, Kirkland, Redmond, and all cities statewide. Local expertise, fast service.