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Accounting Specialist (Billing)

GSI Environmental Inc.
United Statesfull_timeVerifiedPosted 10 Feb 2026

About the role

Job DetailsJob Location: Houston, TX - Houston, TX 77098Position Type: Full TimeEducation Level: Associates DegreeTravel Percentage: NegligibleJob Category: AccountingPosition Overview

GSI Environmental Inc., a privately-owned environmental engineering and consulting services firm headquartered in Houston, Texas, has an immediate opening for a Accounting Specialist to support the Accounting Department with an emphasis on Billing. Candidates must be well organized, detail-oriented, and highly motivated, with excellent oral and written communication skills. Applicant must have the ability to coordinate multiple tasks and to work effectively in a team environment with colleagues and customers.

About Us

We are a privately held, employee-owned company offering superior compensation, benefits, and professional development. GSI is highly respected nationally and internationally for the quality of its professional environmental services and the technically advanced projects it has completed over its nearly 40 years of operation.

GSI employs cross-disciplinary teams of environmental engineers and scientists, including toxicologists, geologists, hydrogeologists, ecologists, chemists, oceanographers, and data scientists with seamless collaboration over both technical disciplines and offices. Headquartered in Houston, Texas, GSI operates offices in Texas (Austin and Houston), California (Irvine, the San Francisco Bay Area, and Folsom), Washington (Olympia), Montana (Missoula and Helena), North Carolina (Raleigh), and New York (Syracuse). Our talented staff of environmental professionals perform projects nationwide and internationally.

Responsibilities

Prepare accurate and timely commercial and government invoices with supporting documentation, on a monthly basis in accordance with project-specific contract terms (most common contract mechanisms include Time & Materials, Firm Fixed Price, and Cost Reimbursable);
Effectively communicate with Project Managers regarding contract documents, purchase orders, change orders, and other contract modification, approvals, and any additional services related to billing;
Ability to understand contract agreements, purchase orders, change orders, contract funding and billing requirements;
Review new projects billing setup and monitor the status of existing projects in the accounting system for billing accuracy;
Investigate billing errors, resolve discrepancies, and reconcile unbilled job costs;
Maintain project billing folder and accounting system to ensure all invoices and other project accounting-related documents are readily accessible for project managers and the accounting department;
Submit invoices through various commercial and government payment portals (Serengeti, WAWF, Collaborati, Taulia, etc)
Provide support in contract and job close out process; and
Provide support to other accounting staff and work on special projects as assigned.

Qualifications/Experience
Some college coursework in accounting, finance, or business preferred
Minimum 2 years of experience in billing, invoicing, or accounts receivable
Experience in professional services firm such as engineering, architectural, government or construction industries strongly preferred;
Federal government billing experience, knowledge of iRAPT/WAWF, GSA, and other billing portals a plus;
Government Contracts Billing terms abstraction knowledge a plus;
Knowledge of Deltek Ajera accounting software is preferred;
Proficient in MS Excel, Adobe Acrobat and MS Word;
Excellent analytical and problem solving skills; and
Strong written and verbal communication skills.

Job Perks

Competitive salary and benefits, including a retirement savings plan
Quarterly and year-end bonuses
Paid time off and holidays
Professional development opportunities
Collaborative atmosphere

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Company

GSI Environmental Inc.

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