Flexa
Find a jobDiscover companiesResourcesSign in/up
For employers
< Back to search
Mott MacDonald • Iselin, NJ, US; Philadelphia, PA, US

Principal Water Engineer

Employment type:  Full time
Apply now

Job Description

At Mott MacDonald, we trust our brilliant people to do brilliant things in engineering, management, and development services, supporting multisector project work in over 150 countries. As one of the largest employee-owned companies in the world, we pride ourselves on our ability to deliver exceptional outcomes through our network of 20,000+ talented consultants. With sustainability and innovation at the heart of all our sectors in North America, including, Buildings, Energy, Transportation, and Water.

We believe in empowering our people to excel, learn, and grow, offering diverse opportunities to contribute to career-defining work. Join us and be part of a collaborative environment where your ambitions are united with ours, and you can truly shape your story.

If you share that vision, even if you don’t meet every requirement listed, we’d still love to hear from you. We value potential and diverse perspectives as much as experience. Let’s explore how we can support your growth and help you take the next step in your career, while contributing to an exciting new chapter for Mott MacDonald in North America.

We are seeking an experienced Principal Water Engineer to lead the delivery and growth of stormwater, CSO, LTCP and flood risk services across New Jersey, and Eastern Pennsylvania. This role focuses on solving complex flooding, drainage, and resilience challenges for municipal, utility, and infrastructure clients.

The successful candidate will bring deep expertise in hydrology, hydraulics and NJ regulatory processes. Extensive experience navigating regional regulatory frameworks, and a proven track record delivering large-scale stormwater, flood mitigation, and CSO programs is preferred. This individual will act as a technical leader, client advisor, and mentor, driving high-quality project delivery and supporting strategic growth.

Key Responsibilities:

  • Lead delivery of stormwater management, flood control, and drainage infrastructure projects, including pump stations, storage systems, and conveyance networks
  • Experience with H&H modeling using industry standard tools such as HEC-RAS, HEC-HMS, XP-SWMM, InfoWorks ICM, SWMM, and related platforms
  • Direct floodplain analysis, watershed studies, and hydraulic system modeling across urban and riverine environments
  • Lead permitting and compliance efforts, including:
    • NJDEP Flood Hazard Area (NJAC 7:13)
    • NJ Stormwater Rules (NJAC 7:8)
    • Understanding of NYSDEC and PADEP regulatory processes preferred
    • FEMA/NFIP coordination and floodplain considerations
    • NN Infrastructure Bank (NJEIT) funding
  • Serve as the primary liaison with regulatory agencies and stakeholders (NJDEP, FEMA, USACE, local authorities)
  • Deliver complex programs such as:
    • Flood mitigation and resilience projects (e.g., floodwalls, pump stations, drainage upgrades)
    • Combined Sewer Overflow (CSO) LTCPs and sewer system improvements
  • Review and approve engineering designs, reports, specifications, and cost estimates
  • Lead project execution, managing scope, schedule, budget, and risk
  • Develop innovative, climate-resilient solutions, incorporating future rainfall and flood conditions
  • Support business development through client engagement, proposals, and market growth initiatives
  • Mentor and develop staff, strengthening capability in stormwater, modeling, and flood risk disciplines

Candidate Qualifications & Experience:

  • Bachelor’s or Master’s degree in Civil, Environmental, or Water Resources Engineering
  • Licensed Professional Engineer (PE) (NJ required, NY, or PA preferred)
  • Certified Floodplain Manager (CFM) strongly preferred
  • 15+ years of experience in stormwater, drainage, CSO and flood risk engineering
  • Advanced experience in hydrologic and hydraulic modeling across complex systems
  • Strong background in:
    • Floodplain and floodway analysis
    • Stormwater management design (BMPs, green infrastructure, subsurface systems)
    • Large-scale sewer and drainage network modeling
  • Delivery of major infrastructure and resilience projects, such as:
    • Flood mitigation and post storm recovery programs (including FEMA-funded projects)
    • CSO Long Term Control Plans and wastewater system upgrades
    • Urban drainage and transportation-related stormwater systems
  • Deep understanding of NJDEP, NYSDEC, and PADEP requirements
  • Experience navigating multi-agency permitting and approvals
  • Familiarity with FEMA floodplain management and funding requirements
  • Proven ability to lead complex, multidisciplinary projects
  • Strong client-facing skills with public-sector stakeholders
  • Ability to solve complex, non-routine engineering problems

Benefits & Reward

At Mott MacDonald, our employees have a stake and a voice in our business, providing them with a direct connection to our success through our personal and group performance bonuses. We provide a comprehensive benefit package that includes 401k, medical, dental and vision insurance, short-term/long-term disability, paid holidays, PTO, parental leave, and company paid life insurance.

Individual pay is determined based on several factors such as work location, education, experience, and unique skills.

The expected salary for this position is

Collaboration at Our Core
At Mott MacDonald, we believe great ideas happen when we’re together. Our hybrid approach centers on an in-office culture, with most of your time spent collaborating face-to-face and a minimum of three days per week in the office. We balance flexibility with connection, so you and your manager can choose how to meet client, team, and personal commitments.

Equal opportunity is the law.

We seek to promote fair employment procedures and practices to ensure equal opportunities for all. We encourage individual expression in our workplace and are committed to creating an inclusive environment where everyone feels they have the opportunity to contribute.

  • English version
  • Spanish version
  • Chinese version

All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, age, protected veteran status, creed, marital status, sexual orientation, gender identity, citizenship status or disability status.

Apply now

Company benefits

Accrued annual leave
Adoption leave – 26 weeks full pay
Annual bonus
Annual pay rises
Bank holiday swaps
Bike parking
Book swaps
Buddy scheme
Buy or sell annual leave
Carer’s leave – up to 5 days, two of which are paid
Compassionate leave
Critical Illness Insurance
Cycle to work scheme
Dental coverage
Employee assistance programme
Employee discounts
Enhanced maternity leave – 26 weeks full pay
Enhanced paternity leave – 2 weeks
Enhanced pension match/contribution – matched up to 7%
Enhanced sick pay
Ergonomic workstations
Eye Care Support – Eyecare vouchers
Faith rooms
Fully stocked snack cupboard
Further education support
Health assessment
In house training
Income protection
L&D budget
Learning platform
Life assurance
Life insurance – 4 x salary
Lunch and learns
Meditation space
Meditation space
Mentoring
Modern office
On-site shower
On-site yoga classes
Open to part time work for some roles
Open to part-time employees
Pregnancy loss leave
Pregnancy support
Private booths
Private GP service – Private Medical care for all UK staff
Professional subscriptions – We pay for your primary professional annual subscription
Referral bonus
Religious celebration leave
Reservist leave – 10 days leave
Returnship
Salary sacrifice
Share options
Shared parental leave – We match up to 24 weeks full pay
Study support
Tax-free childcare
Teambuilding days
Theme park discounts
Travel loan
Women’s health leave
Menopause support
Women’s health support
Collaboration spaces

Working at Mott MacDonald

Company employees:

18,000 worldwide

Gender diversity (m:f:n-b):

0:35:65

Hiring in countries

Australia

Bulgaria

Canada

Czechia

Germany

Hong Kong

India

Indonesia

Ireland

Italy

Japan

Malaysia

New Zealand

Awards & Accreditations

Best Employee Wellbeing

Top 5 - Best Employee Wellbeing

Flexa awards 2026
Best Career Progression

Top 10 - Best Career Progression

Flexa awards 2026
2nd - Best Career Progression

2nd - Best Career Progression

Flexa awards 2025
3rd - Most Family Friendly Company

3rd - Most Family Friendly Company

Flexa awards 2025
Best Work-Life Balance

Top 5 - Best Work-Life Balance

Flexa awards 2025
Most Flexible Company

Top 5 - Most Flexible Company

Flexa awards 2025
Best Workplace Culture

Best Workplace Culture

Flexa awards 2025

Other jobs you might like

  • Mott MacDonald

    Senior Water Resources Project Manager

    Cincinnati, OH, US; Lexington, KY, US; Cleveland, OH, US

Flex spring

Join the mailing list

Get the latest insights and expert guidance on job hunting, career progression, and creating thriving workplaces.

Enter your email
  • About us
  • Contact us
  • FAQs
  • Info for employers
  • Join Flexa
  • Legal
  • Live feed
  • Pioneer awards
  • Resources
  • Sign in/up
  • The Flexa awards
Flexa
Experience mentoring and developing engineering teams
  • Willingness to travel to project sites and attend key meetings as required as needed
  • Saudi Arabia

    Serbia

    Singapore

    South Korea

    Spain

    Taiwan

    Tanzania

    Thailand

    United Arab Emirates

    United Kingdom

    United States

    Office Locations

  • Mott MacDonald

    Principal Project Manager - Civil Transportation

    New Orleans, LA, US

  • Mott MacDonald

    Principal Engineer Geotechnical

    $180,000 – $200,000 per annum

    Westwood, MA, US; Linthicum Heights, MD, US

  • Mott MacDonald

    Principal Marine Structures Engineer

    $168,000 – $205,000 per annum

    Arlington, VA, US

  • Mott MacDonald

    Project Manager Water

    $125,000 – $153,000 per annum

    New York, NY, US