Find answers to all your questions.

1. What is PIPE-R™ Reservoir System?

PIPE-R™ Reservoir System is a subsurface drainage and storage system made of high-density polyethylene (HDPE) corrugated pipes used to preserve valuable land and water resources. It is a substitute for conventional retention and detention ponds and can be placed under anything that is non-structural such as parking lots, drive-throughs, pavements, landscaped areas and lawns, playgrounds, athletic courts and fields, dog parks.

2. What is a BPU or Bundled-Pipe-Unit?

A bundled-pipe-unit (BPU) is a combination of five 4-inch HDPE corrugated pipes, arranged in a two-pipes-over-three-pipes configuration. The pipes are bonded together into a single unit using polyester tie-straps. The patented design improves the structural integrity of the pipes by enhancing its resistance to vertical compressive loads and increment of the voids for storage. BPUs are available in two standard lengths of 42 inches and 88 inches, referred to as BPU-42 and BPU-88, respectively. These standard sizes can be customized to fit in any configuration and site constraints.

3. What are PIPE-R™ cubes?

PIPE-R™ cubes are rectangular-shaped units of BPUs stacked in vertical and horizontal orientations then banded together using polyester straps. The cubes are formed by the placement of different layers of the stacked BPUs. The cubes can be placed side-by-side in an excavated area to fit the design storage volume and site constraints. PIPE-R™ cubes arrive to the job site ready for installation.

4. Do PIPE-R™ cubes come in different sizes?

PIPE-R™ Reservoir System are readily available in three standard cube formats. The three standard cube sizes are:

  • PIPE-R1890 – 88” x 88” square area
  • PIPE-R90 – 88” x 42” square area
  • PIPE-R424 – 42” x 42” square area

The height of a PIPE-R™ cube varies of a single BPU-layer of 8.625 inches high to a maximum of seven BPU-layers (61 inches) for load bearing systems and 10 BPU-layers (87 inches) for non-load bearing systems.

5. What is a PIPE-R™ chamber?

A chamber is a collection of BPUs or cubes placed adjacent to one another to create a single unit of reservoir system with defined maximum width and length based on usage.

6. What is the maximum length of a PIPE-R™ chamber?

The maximum length of a PIPE-R™ chamber is 100 feet.

7. What is the maximum width of a PIPE-R™ chamber?

The maximum width of the PIPE-R™ chamber allowed for installation in a load bearing system is 11 feet and for non-load bearing system is 15 feet. An 11-foot wide system (PIPE-R11W) equates to the combination of one PIPE-R1890 and PIPE-R90 laid side-by-side. A 15-foot wide system (PIPE-R15W) equates two PIPE-R1890 cubes adjacent to each other without a separation. If the site conditions require wider sections to achieve the design storage volume, then more rows of the chamber can be placed adjacent to each other and separated by a minimum of 3 feet or 2 feet embedment materials for load bearing (paved with vehicular traffic) or non-load bearing systems (unpaved and no vehicular traffic), respectively.

8. How do I size a PIPE-R™ Reservoir System?

Sizing of PIPE-R™ Reservoir System for stormwater storage and reuse is based on the hydraulic needs, catchment area, desired efficiency, and target performance required by regulatory agencies. ECS will provide a PIPE-R™ conceptual layout to the design engineer based on information provided to ECS including the storage volume, available area for the system, seasonable high groundwater table (if applicable). The design engineer is responsible for the accurate determination of the required storage volume, piping elevations, outfall structures, available area, and all other local regulations for the final design. ECS created a PIPE-R™ Reservoir System sizing calculator available to design engineers upon request.

9. Is there any software I can use to model the PIPE-R™ Reservoir System?

Currently, design engineers can use stormwater modeling software such as HydroCAD and ICPR for the design of the PIPE-R™ Reservoir System storage requirements and sizing. General design details are presented to guide the design engineer in sizing the PIPE-R™ Reservoir System at any project site. ECS has engineers on staff to assist design engineers in determining the number of cubes and/or BPUs – vertical depth and horizontal spread – based on the storage volume requirement and site conditions. A guide sheet on how to model PIPE-R™ Reservoir System in HydroCAD is presented in the Appendix of the PIPE-R™ Design Guide.

10. How is the PIPE-R™ Reservoir System used to manage stormwater runoff?

The PIPE-R™ Reservoir System can be used as a detention, retention and/or a reuse (harvesting) system.

11. What is a PIPE-R™ detention system?

PIPE-R™ detention system is designed to detain and discharge stormwater runoff through a controlled outfall structure. The system is wrapped with an impermeable geotextile cloth to prevent water from flowing in and out of the system. If the parent soils will not allow infiltration, a non-woven geotextile fabric may be used in place of the impermeable liner.

12. What is a PIPE-R™ retention system?

PIPE-R™ retention system is designed to collect stormwater runoff through an inflow conveyance structure and exfiltrate into the surrounding soil. The system is wrapped with a permeable geotextile cloth to allow water to flow in and out of the system while preventing soil particles from migrating into the system.

13. What is a PIPE-R™ reuse (harvesting) system?

PIPE-R™ reuse (harvesting) system is designed to store stormwater runoff and/or rainwater and reuse it for non-potable applications such as irrigation, washing vehicles, flushing toilets, fire suppression, etc.

14. Can I use an underdrain with a PIPE-R™ Reservoir System?

Yes. Installation of an underdrain is an acceptable practice. The underdrain may be installed adjacent to or under the PIPE-R™ Reservoir System.

15. What type of geotextiles do I use to wrap the PIPE-R™ Reservoir System?

The minimum specifications for the geotextiles are as recommended in AASHTO M 288 – Standard Specification for Geotextile Specification for Highway Applications or as approved by the design engineer. Refer to the PIPE-R™ Installation Guide at for a list of some acceptable geotextiles.

16. How do I install the PIPE-R™ Reservoir System?

The PIPE-R™ Reservoir System is typically installed by a utility site contractor. For detailed information about the installation of the PIPE-R™ Reservoir System, refer to the PIPE-R™ Installation Guide at

17. Does PIPE-R™ Reservoir System require bedding material?

Bedding material is required to support the surcharge loads and provide a stable base underneath the PIPE-R™ Reservoir System. The material for the bedding layer of an installed PIPE-R™ Reservoir System could be of compacted sand and/or stones to allow for exfiltration, if needed. ECS recommends for the base (bedding) material, a minimum bearing capacity of 2000 pounds per square foot (lb./ft2), or as recommended by the design geotechnical engineer based on the expected overburden load. Furthermore, recommended sub-base and base materials, as per design drawings or design engineer, are required above the system to provide firm support to the surface pavement load and as structural backfill.

18. What types of bedding material do I use?

The material for the bedding layer of an installed PIPE-R™ Reservoir System could be of compacted sand and/or stones to allow for exfiltration, if needed. As per the pavement design requirements, refer to AASHTO M 145 and M147 for the appropriate sub-base and base materials for the pavement. If stone is used as sub-base and/or base material for a pervious pavement, the porosity of the stone could be used to provide additional storage. The typical porosity of backfill aggregates (using #57 stone) is 40 percent. For additional strength in load bearing systems, geogrids are recommended to provide tensile strength to the sub-base and/or base materials. For a list of acceptable fill materials, refer to Table 14 in the PIPE-R™ Information Guide.

19. Can PIPE-R™ Reservoir System accept traffic loads?

Yes. The PIPE-R™ Reservoir System has been third-party verified by The Stormwater Management Academy at the University of Central Florida to meet and exceed AASHTO H-20 and HS-20 loading standards. Testing summary and full testing report are available at The PIPE-R™ Reservoir System can receive traffic loads – 24 inches is the minimum recommended cover depth. No heavy equipment is allowed directly on the PIPE-R™ Reservoir System until a minimum cover depth established by the engineer is achieved.

20. What is the lifespan of the system?

PIPE-R™ Reservoir System has a minimum design life of 50 years. See the AASHTO LRFD BRIDGE DESIGN SPECIFICATIONS manual for the specifications for buried HDPE plastic pipes.

21. How do I maintain the PIPE-R™ Reservoir System?

Adequate overall system performance is achieved by the application of proactive maintenance programs using upstream control structures and inspection/maintenance ports within the PIPE-R™ Reservoir System. The manufacturer recommends designers and owners focus on pre-treatment as the best approach to maintaining any underground system. Pre-treatment options are sumps, baffle boxes, inlet protection devices, inlet box screens, trash guards, or any other pre-treatment device as specified by the design engineer and approved by the local regulatory agency. Inspection/maintenance ports can be installed anywhere throughout the PIPE-R™ Reservoir System at the design engineer’s discretion. Water is pumped into the PIPE-R™ System through maintenance ports to suspend fine particles. The particles are extracted with a vacuum truck. Maintenance should be performed on all pre-treatment devices per the manufacturer’s specifications. For more information about the maintenance and clean-up of the PIPE-R™ Reservoir System, refer to the PIPE-R™ Operation and Maintenance Guide.

22. How can I purchase PIPE-R™ Reservoir System?

PIPE-R™ Reservoir System can be purchased through the manufacturer’s licensed distributors: The Rain Collectors and HydroVault Systems Inc.