Sendero Townhome Case Study: Solving Water Holding Tank Issues

When the city of Everett added a last-minute requirement for an on-site water holding tank, Washington Stormwater had it delivered and installed within three days. That response was part of a larger stormwater management program that kept the Sendero Townhome development in full compliance from groundbreak to completion.

Project Overview: Stormwater Compliance on a Residential Development

Sendero Townhome is a single-family condominium development in Everett, WA. Like most residential construction projects in Washington State, it came with a full stack of regulatory requirements before a drop of water could be discharged.

Washington Stormwater was brought in to manage CESCL compliance, water quality sampling, and monthly discharge reporting for the duration of construction. The site’s wet conditions added pressure to an already compliance-heavy project, and when the city introduced a water holding tank mandate mid-project, the team needed to move fast.

Washington Stormwater’s Solution

• 5,000-Gallon Water Holding Tank: Washington Stormwater supplied and installed a 5,000-gallon settling tank to temporarily hold stormwater during heavy rain events, controlling discharge timing and preventing flooding and erosion.
• CESCL Compliance Program: The team developed and managed a full erosion and sediment control plan for the site, including silt fencing, sediment basins, and ongoing inspection documentation required by the state.
• Stormwater Treatment: The holding tank doubled as a treatment system, using hydrodynamic separators and filtration units to remove pollutants before discharge, ensuring water met environmental standards at the point of release.
• Monitoring and Maintenance: Washington Stormwater implemented a proactive inspection and maintenance schedule to keep the system performing reliably throughout the project.

What Washington Stormwater Delivered

• Weekly site inspections by certified CESCL inspectors, with direct engagement with on-site contacts to address maintenance and compliance concerns in real time.
• Water quality sampling at the discharge point during every CESCL inspection, providing an independent data point alongside contractor samples.
• Monthly Discharge Monitoring Reports (DMRs) compiled from both contractor and inspector data and submitted to the Washington State Department of Ecology.
• A 5,000-gallon settling tank delivered and installed within three days of the city’s mandate.

Delivered Fast, Compliant All Season

The three-day tank installation is worth noting because city mandates mid-project don’t come with a lot of lead time. Washington Stormwater’s ability to respond quickly kept the project on schedule and avoided any compliance gap.

Over the course of the project, consistent CESCL inspections, accurate water quality sampling, and timely DMR reporting kept Sendero Townhome in good standing with both the city and the Department of Ecology. The development wrapped up with no compliance violations and a stormwater system that protected the surrounding neighborhood from flooding and runoff.

Josh Aero Construction shared their experience: “Working with Washington Stormwater was a pleasure. Their team provided realistic solutions for our wet job site, adhered to city rules, and promptly delivered materials. Their expertise turned water challenges into advantages, decreasing costs and saving time. We look forward to future collaborations.”

Stay Compliant From Groundbreak to Completion

Washington Stormwater handles CESCL compliance, water quality sampling, and stormwater treatment so your site stays clean and your project stays on schedule. Call us at (360) 625-8366 or request a quote below.