Stream map
| Stream | Quantity evidence | Planning role | Boundary to verify |
|---|---|---|---|
| Fresh process water | Dedicated meter or isolated interval; litres or gallons per vehicle | Baseline, make-up and fresh-only wash steps | Meter boundary, tariff, pressure and equipment requirement |
| Reclaimed wash water | Reclaim meter or tank balance; measured return and delivery | Offsets eligible process demand | Treatment performance, compatible wash steps, exposure and labeling |
| Spot-free permeate | Measured RO production and rinse volume | Final-rinse demand and product-water storage | Actual feed conditions, membrane performance and final-rinse quality |
| RO reject | Feed minus permeate or verified recovery | Potential reclaim input or discharge load | Chemistry, treatment compatibility and approved routing |
| Carryout / evaporation | Measured study, facility balance or entered estimate | Non-returning loss that limits closed-loop recovery | Weather, vehicle type, blowers and wash configuration |
| Backwash / purge / sludge | Cycle volume, frequency and service records | Operating water and waste balance | Waste characterization, handling and lawful disposal |
| Sewer discharge | Discharge meter or defensible water balance | Sewer volume and cost baseline | Utility acceptance, pretreatment and billing method |
| Stormwater | Physically separate drainage evidence | Outside the reclaim quantity loop | Prevent wash wastewater from entering storm drains unless explicitly authorized |
Measurement record
- Meter IDs, units, multipliers, start/end readings and exact interval.
- Vehicles processed, wash packages, test washes and downtime.
- Fresh, reclaim and permeate production or delivery measurements.
- Tank working levels, reserve and overflow or bypass events.
- RO feed, permeate, reject and operating hours at actual conditions.
- Backwash, purge, cleaning and sludge-handling events.
- Current tariff, sewer method, equipment data and authority checks.
A loop is not lossless. Carryout, evaporation, reject, backwash, purge, leaks and maintenance prevent 100% recovery. Never count the same returned volume as both reclaim and avoided discharge without a complete boundary.
Reference boundary. Do not convert an indicative value into a universal design, health or legal requirement. Check the cited source, laboratory context, certified claim and applicable jurisdiction.
Sources
- U.S. EPA WaterSense at Work — Vehicle Washes
- U.S. Department of Energy — Vehicle Wash Water-Use Estimating Methods
- International Carwash Association — Water Use, Evaporation and Carryout
- U.S. Department of Energy — Handbook of Water Use and Conservation