#1Northwest Pipe Company INVESTOR PRESENTATION March 2022 WWW.NWPIPE.COM#22 FORWARD LOOKING STATEMENTS Statements in this presentation are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act of 1934, as amended, that are based on current expectations, estimates, and projections about the Company's business, management's beliefs, and assumptions made by management. These statements are not guarantees of future performance and involve risks and uncertainties that are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed or forecasted in such forward- looking statements as a result of a variety of important factors. While it is impossible to identify all such factors, those that could cause actual results to differ materially from those estimated by the Company include changes in demand and market prices for its products, product mix, bidding activity and order cancelations, timing of customer orders and deliveries, production schedules, price and availability of raw materials, excess or shortage of production capacity, international trade policy and regulations, changes in tariffs and duties imposed on imports and exports and related impacts on the Company, the Company's ability to identify and complete internal initiatives and/or acquisitions in order to grow its business, the Company's ability to effectively integrate ParkUSA, Geneva Pipe and Precast Company, and other acquisitions into its business and operations and achieve significant administrative and operational cost synergies and accretion to financial results, impacts of recent U.S. tax reform legislation on the Company's results of operations, adequacy of the Company's insurance coverage, supply chain challenges, labor shortages, operating problems at the Company's manufacturing operations including fires, explosions, inclement weather, and natural disasters, impacts of pandemics, epidemics, or other public health emergencies, such as coronavirus disease 2019, and other risks discussed in the Company's Annual Report on Form 10 K for the year ended December 31, 2020 and from time to time in its other Securities and Exchange Commission filings and reports. Such forward-looking statements speak only as of the date on which they are made, and the Company does not undertake any obligation to update any forward-looking statement to reflect events or circumstances after the date of this release. If the Company does update or correct one or more forward-looking statements, investors and others should not conclude that it will make additional updates or corrections with respect thereto or with respect to other forward-looking statements. NON-GAAP MEASURES The Company is presenting backlog including confirmed orders, adjusted net income, and adjusted diluted net income per share. These non-GAAP financial measures are provided to better enable investors and others to assess the Company's results and compare them with its competitors. This should be considered a supplement to, and not a substitute for, or superior to, financial measures calculated in accordance with GAAP. ☐ Northwest Pipe Company Northwest Pipe Company#3ABOUT NORTHWEST PIPE COMPANY Leading manufacturer of water-related infrastructure products including engineered steel pressure pipe and precast and reinforced concrete products Founded in 1966 and headquartered in Vancouver, WA Strategically positioned to meet North America's growing needs for water and wastewater infrastructure · • Largest, most flexible capabilities in the water transmission market Supplier of choice for long-distance, raw-water transmission programs Provides solution-based products for a wide range of markets under the Park USA, Geneva Pipe and Precast, and PermalokⓇ product lines Widely-recognized reputation for quality, service, and manufacturing capabilities Strong relationships with agencies, engineers, and contractors built over 50+ years 13 strategically located manufacturing facilities Twelve in the U.S. and one in San Luis Rio Colorado, Mexico 3#4LARGE ADDRESSABLE MARKET OPPORTUNITY 4 Steel Pressure Pipe Concrete Pipe & Precast¹ Solution-based products serve the steel pressure pipe and concrete and precast structure market for a wide range of use cases including water transmission, plant piping, tunnels, and river crossings. NWPX's Share: $260 M (49%) NWPX's Share: $125 M (4%) Total Addressable Market: $450 - $600 M Total Addressable Market: $2 - $5 B Note: Market share based on net sales as of the full year ended December 31, 2021. NWPX's share for the Concrete Pipe & Precast market represents pro forma net sales for the Company's Precast segment as if the acquisition of ParkUSA had occurred on January 1, 2021. Market sizes based on internal estimates using information as of December 31, 2021. Includes North America. The Company's ParkUSA operations primarily serve the water control systems market. ☐ Northwest Pipe Company 1.#5STRATEGIC FOOTPRINT WITH CUSTOMER ACCESS ACROSS THE U.S. 20-year water infrastructure Investment need by state Northwest Pipe is well positioned to serve its customers and states that are most in need of water infrastructure investment. ☐ Northwest Pipe Company Water CAPEX, US$ 1 < $1 Billion > $1 Billion <$5 Billion > $5 Billion <$10 Billion > $10 Billion 1. Source: Bluefield Research. CORPORATE HEADQUARTERS ENGINEERED STEEL PRESSURE PIPE PLANTS PRECAST INFRASTRUCURE AND ENGINEERED SYSTEMS PLANTS Note: Indicators in Utah in red signify Geneva plants and indicators in Texas in red signify ParkUSA plants. 5#6FAVORABLE MARKET DYNAMICS¹ • U.S. water consumption equal to 82 gallons per person per day • . • 6 billion gallons of treated drinking water is lost every day from leaks that's 14-18% of treated water lost!! - This equates to 2.1 trillion gallons of non-revenue water loss per year More than ~12,000 miles of water pipes were planned to be replaced by drinking water utilities across the US in 2020 alone AWWA estimates $1 trillion needed to restore and expand the US water system to meet the growing population's needs Capex spending for water 2018-2027 forecast: $303 billion $33 billion Texas U.S. Water Supply Construction Starts² ($ Billlons) 12.4 14.1 13.4 12.3 6 23.3 22.4 20.2 17.2 16.8 • . $79 billion in the West ($44 billion in California) The steel pressure pipe market has momentum as a result of the long project timelines ☐ Northwest Pipe Company 2017A 2018A 2019A 2020A 2021A 2022E 2023E 2024E 2025E Sources: 1. American Society of Civil Engineers "2021 Infrastructure Report Card" Bluefield Research and American Water Works Association. 2. Chart source: Dodge Data & Analytics – 4th quarter 2021.#7MySpeed MT2000ERF WS SA304 P4650043 Northwest Pipe Company Saginaw Plant Expansion 2013 DEMAND DRIVERS st Pipe Com • 7 • • • • • Housing starts Population growth and new population centers intensify the need for new water infrastructure Rising demand for developed water sources Substantial underinvestment in water infrastructure over the past several decades Aging water and wastewater systems Heightened need for upgrades, repairs, and replacements of existing water infrastructure Increasingly stringent regulatory policies Drought conditions Existing water sources have become stressed leaving continued opportunities for growth in North American infrastructure#8COMPETITIVE STRENGTHS Well-Positioned Industry Leader • • • Largest, most flexible capacity in the market Skilled project management group In-house fabrication capabilities provide a complete engineered system Added core competency in precast concrete provides new opportunities for potential future expansion and/or acquisitions Water control systems acquired via ParkUSA provide unique advantages for growth in both the commercial and residential construction markets . PermalokⓇ provides superior product to the microtunneling market Dedicated staff focused on improving operational efficiencies at the plant level (internal programs, lean initiatives, etc.) National footprint enables low freight costs 8#99 SOCIAL AND ENVIRONMENTAL RESPONSIBILITY We are highly focused on investing in our workforce, health and safety programs, social initiatives, and improvements to our environmental stewardship. Health & Safety Diversity & Inclusion Environmental Stewardship • • • • Compliance-driven approach Industry-leading safety performance over the last four years1 • Average total recordable incident rate: 2.48 Average days away rate: 0.52 Proactive and precautionary COVID-19 measures in place Comprehensive Employee Assistance Program ("EAP") Monthly Safety Plan Meetings, 'No Days. Away' Safety Awards, and employee Safety Day Strive for continuous improvement ☐ Northwest Pipe Company • Focused on recruiting diverse leadership across the Company • 46% of U.S. employees from underrepresented racial/ethnic groups 11% of U.S. employees are female Affirmative Action Program with goals for equal representation in the markets in which we operate • Strive to ensure pay equity for all • • • Continuing to invest in improvements to drive efficiencies and reduce carbon footprint • Enhanced coating and lining. processing to reduce emissions Upgraded facility lighting Comply with environmental laws and regulations while minimizing waste employees regardless of identity Aim to increase transparency on employee representation Note: As of December 31, 2021. 1. Calculated in accordance with the Occupational Safety and Health Administration's record keeping requirements.#10WIDE RANGE PRODUCT CAPABILITIES 00 000000 NORTHWES FPE SENATH METIVE Engineered Steel Water Pipe Storm Trooper Stormwater Technology Storm Trooper 541 PermalokⓇ Steel Casing Pipe RCP & Precast Concrete Wastewater Technology E Trooper Lined RCP Pipe & Manholes Pump Lift Stations Bar-Wrapped Concrete Pipe 10 10#11GROWTH STRATEGY Northwest Pipe's growth strategy is to expand into a broader water market to capitalize on the unique attributes of its market position, capabilities, reputation, nationwide sales, and distribution footprint. Northwest Pipe's goal is to create transformational growth and profitability in order to drive shareholder value. The strategy is two-pronged: 1. Growth in precast-related market through expansion or acquisitions. 2. Maximize steel pressure pipe water transmission business by making significant progress through cost reduction measures and Lean manufacturing to drive further efficiencies, while being opportunistic with the limited but identified potential acquisition opportunities (once the integration of ParkUSA is complete). 11#12ACQUISITION CRITERIA Northwest Pipe's acquisition criteria focuses on organic growth, strong margin characteristics, solid asset efficiency and a positive cash flow profile. Priorities Include Accretive to earnings • Asset efficiency • Strong financial performance • • . Industry and geographic location aligns with strategic growth plan Performance indicators based on revenue and EBITDA thresholds Strong brand reputation and relationships in industry Experienced management teams ☐ Northwest Pipe Company 12#13RECENT STRATEGIC ACQUISITIONS GENEVA PIPE AND PRECAST • • Completed the acquisition of Geneva Pipe and Precast on January 31, 2020 for $49.4 million . Concrete pipe and precast concrete products, plants located in Utah Products used for waste and storm water applications by cities, municipalities and local governments Development of innovative products and extend the life of concrete pipe and manholes for sewer applications • TRANSACTION RATIONALE Significantly expands addressable market Serves smaller scale, more transactional projects Cross-sell products across combined footprint · PARKUSA . • • Strong financial performance with attractive profit margins and top-line growth Scalable business model with faster cash conversion cycle • • • Strong brand reputation and relationships in the industry Completed the acquisition of ParkUSA on October 5, 2021 for $88.41 million Technology leader in water infrastructure • Focused on precast concrete and steel fabrication based water products • • Stable, more transaction oriented revenue model with solid margin characteristics Solutions provider with strong brand reputation and customer relationships Approximately 280 employees at December 31, 2020 with annual revenues of $66.5 million Founded in Houston, Texas in 1984 by the Eberly family TRANSACTION RATIONALE • • Opportunity to continue expansion into precast and adjacent water segments Attractively positioned with a foothold in Texas water market Scalable product mix serves a diverse range of end markets • Roll-out strategy introduces ParkUSA process to existing Northwest Pipe locations 1. subject to a post-closing adjustment based on changes in net working capital. 13#14PRODUCT SPREAD STRATEGY O • Begin where we already have production facilities; control production, low cost of entry Initial focus on wastewater products, stormwater, and water distribution Plans to emphasize cross-training across facilities • Expansion would require retrofit of existing facilities from 2022-2024 P&H 105/5 Ele PARK PARK PARKE 070 LET OPARKY CIONES PAAR 150 QUALITY CONTRO PRODUCTION SA ROCHA 7/16/15 ANAL PARK! 14#15STRONG BACKLOG DRIVES SOLID PERFORMANCE SPP Backlog¹ ($ Millions) Revenue ($ Millions) $202 $138 $173 $121 $116 $103 $88 $66 $252 $258 $221 $272 $269 $290 $239 $221 $226 $173 $172 $149 $133 $279 $260 $242 $743 $442 15 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 ☐ Northwest Pipe Company 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 ■SPP Revenue ■Precast Revenue Note: Precast refers to Precast Infrastructure and Engineered Systems & SPP refers to Engineered Steel Pressure Pipe. 1. Backlog includes confirmed orders (projects for which the Company has been notified that it is the successful bidder, but a binding agreement has not been executed). 2. Pro forma net sales for the Company's Precast segment would have been approximately $48 million if the acquisition of Geneva had occurred on January 1, 2020 as opposed to January 31, 2020. 3. Pro forma net sales for the Company's Precast segment would have been approximately $125 million if the acquisition of ParkUSA had occurred on January 1, 2021 as opposed to October 5, 2021.#16• • Q4 2021 HIGHLIGHTS Record backlog of $290 million including confirmed orders 1 Q4 2021 backlog marks 14th consecutive quarter with a backlog exceeding $200 million Completed acquisition of ParkUSA on October 5, 2021 SPP Backlog¹ ($ Millions) Net Sales by Segment² ($ Millions) $290 $276$270 $258 $273 $58.1 $224 $246$231$221 $210 $234 $11.3 $71.6 $31.0 Q2'19 Q4'19 Q2'20 Q4'20 Q2'21 Q4'21 Q4 2020 Q4 2021 ■SPP Precast Gross Profit by Segment ($ Millions) $10.9 $8.7 $1.5 Q4 2020 $4.9 Q4 2021 SPP Precast Note: Precast refers to Precast Infrastructure and Engineered Systems & SPP refers to Engineered Steel Pressure Pipe. 1. Backlog includes confirmed orders (projects for which the Company has been notified that it is the successful bidder, but a binding agreement has not been executed. 2. Precast net sales for Q4 2021 include an $18.0 million contribution from the acquired ParkUSA operations. 16#17STRATEGIC AND OPERATIONAL INITIATIVES 1. Take every precaution to keep our employees safe through the ongoing pandemic 2. Integrate Park USA acquisition as quickly and as efficiently as possible 3. Improve performance through a persistent focus on margin over volume 4. Continue to implement cost reductions and efficiencies at all levels of the Company 5. Identify strategic opportunities to grow the Company through expansion or acquisitions following the successful integration of Park USA NORTHWEST VE AX-93 17 94 15 462 (33 #427 033 850 Northwest Pipe Company#18INVESTMENT HIGHLIGHTS Well-positioned to benefit from historic strong backlog and growing market demand for both new and existing water infrastructure upgrades Large addressable market provides opportunities for further expansion Diversification strategy helps reduce impacts from market cyclicality and improve free cash flow generation Variable cost structure provides financial flexibility Strong balance sheet ● Experienced management team with over 100 years of collective industry experience 18#19Q&A OVERSIZE LOAD OL COME#20Northwest Pipe Company INVESTOR PRESENTATION March 2022 WWW.NWPIPE.COM