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The City of Portland, Oregon

Portland Water Bureau

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Customer Service: 503-823-7770


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Commercial Water Efficiency Survey

Commercial Water Efficiency Survey

A water efficiency survey is an assessment of the facility’s water using equipment and processes to identify potential water savings opportunities. A water efficiency survey can range from simple to complex depending on the type of facility being reviewed and the amount of time the customer is willing to invest in the review.

These surveys, carried out by Water Bureau staff, are free of charge. The outline below describes the basic information needed and the process for completing a relatively complex water efficiency survey. Portland Water Bureau staff are available to discuss assistance options. 

Call (503) 823-4527 or email to schedule a survey.

Prepare for Site Visit

To make the most of the time spent on site, it is helpful to obtain as much information about the physical characteristics of the site beforehand. Some of the tasks that should be completed in advance so that the auditor is familiar with what to expect during the site visit are listed below:

  • Gather, review, and tabulate water/wastewater records, billings, and costs. Review wastewater pretreatment inspection reports if available.

  • Identify contact person(s) (plant engineer, maintenance staff, plant manager).

  • Send letter to contact person confirming appointment and outlining scope of site visit and information needed.

  • Review plant plans, schematics of process flow, lot size, irrigated area(s), building footprints, etc. if they can be obtained in advance of visit.

  • Gather and review operating records from facility operator or engineer. Examples of data to collect are:

    • Cooling towers treatment, sub-meter records.
    • Boiler maintenance data.
    • Irrigation systems: clock run times, number of runs per week, area per zone or heads per zone and head types, sub-meter data, if any.
    • Readings from all meters that track water/wastewater use in the plant.
    • Pump run time records.
    • Energy use records.
    • Staffing numbers, visitors, shifts, hours of operation for various water using machinery and the building in general, etc.
    • Information on other activities and processes that use significant amounts of water.
    • Reports from prior water use or energy surveys conducted for the site.

Conduct Site Visit

During the site visit, gather as much additional data on how the facility is operated and the process flows as possible. Much of this information is shared through meeting with those who operate the facility, but a tour of the site also provides important opportunities to witness the actual operations and to ask additional questions about procedures. At a minimum, the site visit should include the following:

  • Meet with plant personnel. Discuss water uses, water conservation ideas, and any water conservation measures that have been taken in the past or are planned for the future. Discuss and note proposed facility expansions or equipment implementation plans with plant personnel.

  • Tour facility. If allowed by customer, take photos of important water using operations for use in the report and to maintain a visual memory of the site.

  • Identify water sources, individual uses, volumes, disposal methods, losses, treatment chemical uses and costs, plant/site sub-meters. Make flow measurements for major water use streams if they are not sub-metered. Collect water quality samples if reuse of some waste streams is contemplated.

These steps may need to be repeated over the course of a week or two. Each site will be somewhat unique, however, the following are key points or typical water uses to investigate among the BIG sector:

Domestic (Restroom) Uses

  • Toilets and urinals (estimated use per flush and number of occupants and uses per day).

  • Faucets (flow measurement and number of occupants and uses per day).

  • Showers (flow measurement and number of occupants and uses per day).

Commercial Kitchens

  • Dishwashers (Model no., hours of operation, visual inspection, water-saving features).

  • Garbage Disposers (Model no., hours of operation, visual inspection).

  • Plate cleaning troughs (flow measurement, Model No., hours of operation, visual inspection).

  • Ice Making Machines (Model no.; type (cube or flake); pounds of ice produced; visual inspection; air-cooled or water-cooled; flow measurement of once-through cooling flow, where applicable).

  • Ice Cream/Frozen Yogurt Machines (Model no.; visual inspection; air-cooled or water-cooled; flow measurement of once-through cooling flow, where applicable).

  • Water-cooled Refrigeration Units (measure once-through flow rate where possible, model no., and capacity information).

  • Miscellaneous Uses (food thawing, cleaning, etc.).

  • Leaks, drips.

Cooling and Heating

  • Cooling Towers (Capacity, make-up water amounts, hours or period of operation, cooling load, chemical vendor, vendor reports, concentration ratio).

  • Single-Pass (once-through) Cooling (identify uses such as air compressors, vacuum pumps, water-cooled condenser units, product cooling, flow rate, hours of operation, temperature).

  • Evaporative Coolers (capacity, check bleed-off water volume, condition of equip., concentration ratio).

  • Humidifiers (capacity).

  • Boilers/Steam Generators (capacity, steam condensate recovery, leaks, blowdown, "mixing valves").

  • Water-cooled Heat Pumps (measure flow rate if possible, model no., and nameplate data for capacity, contact equipment supplier for use data).

Rinse Processes

  • X-ray/Film Processors (hours of operation, flow rate, automatic shut-off? Is it operational?).

  • Rinse Baths (flow rate, hours/duration of operation, static/constant overflow/counter-current type). Are there any automated controls to manage water make-up, overflow rates, amount of time parts are suspended above tanks for drip back, etc.


  • Type of washer (flow rate, pounds of laundry washed per day, number of loads washed per day).

  • Water Reclamation System in place?

Washing and Sanitation

  • Steam Sterilizers (flow rate, hours of operation, automatic flow shutoff).

  • Ethylene Oxide Autoclaves (flow rates, hours of operation).

  • Manual Washing (method of cleaning, volume of water used).

  • Vehicle Washing (flow rates, condition of equip., hours of operation, water recycle systems).

Landscaping and Decorative Uses

  • Irrigation (area, volume, period of operations, type and condition of equipment, automatic controller or manual).

  • Landscaping (type of landscaping, location of landscaping, site conditions that would affect water use – soil types, slopes, sun exposure, visibility/use of area).

  • Ponds and Fountains (water recycle systems, automatic shut-off).

  • Pools (fill frequency, filter backwash frequency and rate, cover present?).


  • Ingredient (volume and period of operation).

  • Cleaning Operations (rate and operation period).

  • Conveyance (flow rate, hours of operation, automatic shut-off).

  • Water/Wastewater Treatment (reject volume, equipment efficiency).

Data Evaluation

The interpretation of data collected during the site visit and initial data review steps is key to the recommendations provided to the customer. There may be instances where additional data needs to be collected to confirm the accuracy of flow estimates or assure the feasibility of reusing a certain stream of water for another purpose, for example. When flow balances do not seem to match up to actual billings, additional investigation and measurements may be needed to confirm that all water uses have been included and estimates reflect actual site conditions. The data evaluation steps for a typical site efficiency assessment are:

Prepare water balance(s)

Use the information gathered and the measurements taken at the site, estimate quantity and uses of water at the site for various activities. Compare to the annual water consumption records. A water balance allocating at least 90 percent of the water consumption for the site to the water using activities at the site is a reasonable result. If there is more than ten percent difference between estimate and actual total use, review site uses again to ensure that all significant water uses have been considered in the balance. If balance was complete and error free and actual is less than balance, meter may be registering low. Have mainline meter checked for accuracy. If balance is lower than actual use, a leak may exist.

Identify potential conservation actions, savings, and costs

Based on the amount of water used for various operations on site as compared to other more water efficient methods for achieving the same end result, identify potential water conservation and estimate the water savings and implementation costs for the conservation actions considering water, wastewater, energy, and other associated (chemical, labor, transportation, reduced/increased production time, etc.) costs or cost savings, where applicable.

Select cost-effective recommendations

Cost-effective conservation actions for the BIG sector are opportunities that pay for the implementation costs with water, wastewater, and energy savings within 3-5 years. What a particular business considers a reasonable payback period typically depends on the type of facility. Some private industries that see rapid changes in plant infrastructure as a result of product advancements, like the computer industry, may view 6 months as a maximum payback period, while public sector facilities that may use the same facility without much change for 50 years may be comfortable with longer payback periods approaching 5 years or more. The reports developed for customers will include measures that are within the payback identified by that particular customer as an appropriate length to consider. In general projects with paybacks of 5 years or less are thought to be worth including in a list of feasible measures.

Report Preparation

Summarize the findings and recommendations from the water audit process in a short, succinct report that the customer can use to obtain support for implementing projects and for budgeting for them in the next several years. This report should briefly describe the activities on site and the factors that influence water use, provide a consumption history for the site, summarize the results of the water balance, summarize feasible conservation opportunities, including costs, savings (labor, water, sewer, energy, chemicals, etc.), and paybacks and/or return on investment for conservation measures with paybacks of 5 years or less, and a prioritized schedule for completing projects considering other upcoming work at the site into which conservation projects might be incorporated.

Follow-up and Implementation

Provide the customer with a copy of the report and discuss the options and alternatives presented in report. If the customer contact person agrees, include management in these discussions. BIG staff members will maintain contact with the customer’s representative for two or three years as projects are implemented. They will answer questions, provide consumption data, obtain project cost figures, determine before and after water use, and discuss performance and affects (positive and negative) the project has had on plant operations.