About Us

The Company

Founded in 1996 by Diane de Mailly, DDM is a utility submetering design, installation, and reading/billing service company specializing in Commercial, Residential, and Multi-Family properties. Our mission is to provide the tools and services necessary for multi-unit properties to efficiently recover utility costs from tenants. Our unique proprietary software enables an approach to billing that allows managers and property owners to tailor tenant billing directly to tenant leases and according to regional time-of-use rate schedules. We are passionate about the environment and have found that when tenants are responsible for the cost of their equitable share, overall utility usage decreases, benefitting everyone. With a national footprint, DDM is well positioned to meet the growing needs of our core markets. We are proud to be a certified Green Business, as well as a CPUC Woman Owned business in California.

Our Team

Diane de Mailly

Diane de Mailly

Founder and President, DDM

Passionate about the environment, Diane de Mailly provides “green” solutions to multi-tenant properties seeking to conserve energy and drive down utility usage. She pioneered the submetering of after-business hours for her Los Angeles commercial clients, reducing overall consumption and increasing recovery of utility costs in office buildings and plazas.

For several years, Diane has been honored by the Pacific Coast Business Times in its Who’s Who in Clean Tech and Sustainability. A former board member of theVentura Chamber of Commerce, Diane chaired the Green Task Force whose mission is to empower the business community to work green through educational initiatives. A strong advocate of water conservancy, Diane was a two-time appointee to Ventura Water’s Cost of Service and Rate Design Citizen Advisory Committee and was a member of the Water Shortage Task Force.

An active member of the National Association of Women Business Owners, Diane served as Chapter President for 2014-15 and again for 2018-19. She has also served on the NAWBO California Board of Directors since 2015 and has been Chair of the Public Policy Committee. In 2011, the Ventura Chapter of the National Association of Women Business Owners named Diane de Mailly “Woman Business Owner of the Year.” In January 2014, Diane was appointed by the Ventura County Board of Supervisors to the newly established Women’s Economic Roundtable and was elected Chair for the 2015 and 2016 terms. In 2015 and 2016, the Pacific Coast Business Times honored Diane as one of the “Top Fifty Women in Business.” Diane is an Honors graduate of Bryn Mawr College.

Maelynn Dickson

Maelynn Dickson

Chief Executive Officer, DDM

With DDM since 2012, and most recently as Manager of Meter Reading and Billing Services, Maelynn has been responsible for the consolidation of all of our billing accounts into one billing platform; training, supervision, and hiring of staff; systemization of quality control standards; management and analysis of all metering data and integration services; and management of all environmental and conservation services.

Maelynn is a passionate advocate for environmental conservation and sustainability. She earned her B.A. in Geography with a focus on environmental analysis and an M.A. in Geography and The Environment from California State U., Fullerton. Throughout her academic journey, Maelynn specialized in studying the human impacts on the environment and dedicated herself to finding ways to enhance conservation efforts and raise awareness among the general public. She brings great energy and purpose to DDM’s mission to provide building owners and managers with the tools to conserve energy and manage utility costs.

Why Choose DDM Metering Systems Inc.?

The DDM Metering Team, with over 25 years of experience, works directly with you as your utility expert to find the best submetering solution for your specific application. We custom tailor billing to accurately reflect the tenant’s lease terms and any special considerations, such as metered HVAC schedules and regional utility time-of-use charges.

Accurate, on-time billing, and industry-leading customer service function to increase tenant satisfaction, improve retention, and ensure an equitable and timely recovery of utility expenses, thereby improving cash-flow, net operating income, and return on investment.

Our services include design, installation of metering equipment, and maintenance, in addition to our custom utility reading and billing.

With a broad mix of submetering products, billing software and installation design and planning services, DDM Metering is your one stop shop for all your submetering needs. Our team of experienced professionals is here to address your installation, service and billing inquiries or any other questions you may have. Building managers, property owners, residents and tenants in condominiums, apartments, co-ops, commercial buildings, and offices across California count on us for reliable submetering solutions. You can too!

We are a part of the California Green Business Network – City of Ventura

Let Us Automate Your Facilities

Our software automates the manual meter reading and billing processes that currently eats up valuable time every month, giving your team time to focus on more important responsibilities.


Our mission is to help commercial and residential property owners and managers control energy costs
via submetering through equitable allocation based on actual individual usage.
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