We are an environmental engineering firm specializing in the planning, design, and construction of water and wastewater facilities.

United States
Joined May 2009
From our Carollo Engineers family to yours, Happy Independence Day! We hope you have a safe and memorable holiday celebrating with family, friends, and community.
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Carollo Engineers retweeted
.@CarolloTweets is #10 on EC&M's Top 40 Electrical Design Firms list for 2026. Find out more and see the full Top 10 here: bit.ly/4nbdzM9 #ecmmagazine #design #electrical #top40designfirms
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Carollo Engineers retweeted
The upcoming Pure Water Center will provide an additional drought-proof water supply for El Paso. Watch this update youtu.be/1ij_F2T_efY?si=Ona8… on the first-of-its-kind facility that will turn treated wastewater into high-quality drinking water. @PCLConstruction @Sundt @CarolloTweets
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Carollo Engineers retweeted
Rethinking Master Planning In A Data-Rich Environment wateronline.com/doc/rethinki… via @CarolloTweets
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Carollo Engineers retweeted
This week, we accepted the first chemical deliveries at our new chemical building as part of our Phase 1B Improvement Project. A big thank you to our dedicated staff and project partners, @GarneyConstruct and @CarolloTweets.
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Carollo Engineers retweeted
Replying to @CarolloTweets
@CarolloTweets has received a 2026 Honor Award for their work on the Zone 7 Stoneridge PFAS Treatment Facility project for their client, Zone 7 Water Agency. Congratulations! We look forward to celebrating at the EEA Banquet on 2/19/26. Register: acec-ca.org/page/26eeabanque…
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Carollo Engineers retweeted
Replying to @CarolloTweets
@CarolloTweets has received a 2026 Honor Award for their work on the PV Water College Lake Integrated Resources Management Project for their client, the Pajaro Valley Water Management Agency. We look forward to celebrating at EEA on 2/19/26. Register: acec-ca.org/page/26eeabanque…
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Carollo Engineers retweeted
Replying to @CarolloTweets
@CarolloTweets has received a 2026 Honor Award for their work on the PV Water College Lake Integrated Resources Management Project for their client, the Pajaro Valley Water Management Agency. We look forward to celebrating at EEA on 2/19/26. Register: acec-ca.org/page/26eeabanque…
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As we welcome 2026, we’re thankful for the partnerships, teamwork, and innovation that shaped this past year—and excited for everything ahead!
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Sending warm wishes and holiday cheer from all of us at Carollo.
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Carollo's Rosa Yu sat down with WaterWorld to discuss a pilot-scale study on PFAS treatment in GAC-capped drinking water filters. Hear lessons learned, alternatives they’re exploring, and how this process can help other utilities facing PFAS challenges: carollo.com/news/pfas-treatm…
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In a recent Streaming Water podcast, Carollo’s Diana Leonard and John Rehring share how The ABCs of Water Reuse is using bold visuals, clear language, and relatable examples to turn complex engineering into concepts general readers can understand. Listen: carollo.com/news/abcs-stream…
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As semiconductor manufacturing ramps up across the US, so does its demand for water. In WE&T, Carollo’s John Rydzewski explores why conventional zero-liquid discharge systems aren’t enough. See how the industry can rethink water reuse: carollo.com/publications/chi…
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From co-op student to regional reuse lead, Matt Holitzki’s path in the water industry shows how hands-on experience and a passion for sustainability can shape a meaningful career. Learn more about Matt’s journey as a water professional: carollo.com/news/matt-holitz…
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Oregon’s Willamette Water Supply Program is raising the bar for resilient, community-focused water infrastructure. Carollo’s experts break down the project in a recent @WaterOnline article. Read the article to learn more about this incredible project: carollo.com/publications/wws…
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Congrats to @SanDistricts for receiving the 2025 CASA Excellence in Innovation and Resiliency Award! Carollo is proud to have supported this groundbreaking project and contributed to establishing a scalable model for sustainable wastewater treatment across California and beyond.
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As utilities face rising energy costs and growing sustainability demands, one question keeps surfacing: how can wastewater treatment become more energy efficient without compromising nutrient removal? Learn strategies for your facility: carollo.com/publications/red…
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Overcoming consumers' skepticism of water recycling can be tricky, so @CarolloTweets published a guide to help water systems bridge that communication gap. Read more about the ABCs of Water Reuse in #AWWAConnections news.awwa.org/3I1xooQ
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Carollo Engineers retweeted
Building Tomorrow's #WaterInfrastructure: Insights From The Pacific Northwest's Largest Water Conveyance Program wateronline.com/doc/building… via @CarolloTweets
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