FREQUENTLY ASKED QUESTIONS ABOUT RAINWATER &
GREYWATER HARVESTING

FREQUENTLY ASKED QUESTIONS ABOUT RAINWATER &
GREYWATER HARVESTING

I have an existing building that I would like to make “greener”. Can I install a rainwater harvesting system? What about a greywater system?

In existing buildings, rainwater harvesting can be relatively inexpensive when capturing rainwater coming from rooftop downspouts into a storage tank to use for irrigation or cooling tower make-up. Consider cooling condensate as another readily accessible source of harvested water in existing buildings. Storage can be handled in either underground or above-ground tanks. Flushing toilets with harvested water creates more issues in existing buildings, as non-potable lines will need to plumbed to each fixture. 

The cost of adding greywater harvesting systems to an existing building is considerably greater than with new construction. Typically, the showers, lavatory sinks and toilets all run to a single line that connects to the sewer system. Harvesting greywater requires a separate line for the showers and lavatory sinks that is run to the collection tank. This extra plumbing is prohibitively expensive to install in an existing building unless the building is being gutted. But every building is different, and greywater harvesting may be practical in some situations.

How do I decide which type of system or systems is best for my building?

Every building situation is unique – particularly with the availability and usage needs for harvested water. Considerations include:

  • The type of building and usage – offices vs. residential.
  • Availability of greywater from showers, sinks, washing machines.
  • Rain frequency and amounts in your area.
  • Number of toilets and number of building occupants.
  • Land use around the building – amount of landscaping, type of parking facility and stormwater runoff, implications for water storage locations above or below ground.

Contact us for a free analysis to help you decide is water harvesting is right for your project.

Does Water Harvesting Solutions work with homeowners?

Not at this time.  We are primarily focused on the commercial building industry. There are wonderful resources available to homeowners, and we encourage you to visit our Resources Page for a list of suggested contacts and links.

What is the value of water harvesting in LEED Certification?

The latest USGBC certification for LEED is v4, and it added considerable focus on water conservation. Water harvesting efforts can now earn up to 15 points across a number of LEED categories including:

  • Inside water use reduction
  • Outside water use reduction
  • Rainwater management
  • Cooling tower water use reduction
  • Water metering

Visit our LEED Page for more information.

What are the considerations of using harvested greywater for a building?

An efficient greywater system first requires a steady source of greywater. The most abundant source is showers in buildings with full time residents – dormitories, hotels, schools, etc. Manufacturing facilities using large amounts of water in light processing, cooling baths, etc., may also be good candidates for commercial greywater reuse.  Office buildings generally do not produce enough usable greywater to warrant the cost of a system.

When there is an abundant supply of greywater, it can be a more reliable source of water for flushing toilets than rainwater. The amount of shower and sink usage generally ties to the amount of toilet use in a building, so there is almost always a balance in supply and demand for greywater.

Greywater (gray water) harvesting requires additional treatment versus rainwater. This is due to the heavier load of soaps and organic particles that are carried in greywater. The additional filtering and sterilization requirements result in higher costs for a greywater system vs. a rainwater system. While greywater treatment is more complex and therefor more expensive than rainwater harvesting, the reduced storage requirement can often more than offset the higher processing costs. For more information, please visit our page on Greywater Systems. 

Can harvested greywater be used for irrigation?

Yes – The Wahaso treatment process produces high-quality water that is safe for irrigating lawns and landscaping, even for spray irrigation systems. Local codes can be confusing on this matter. Technically, greywater is untreated water from showers and sinks, and many communities have strict codes regarding use of untreated greywater. Our systems convert greywater to On Site Treated Non-Potable Water, and the implications for usage are different, so a careful check of local ordinances is important.

When greywater is used to flush toilets, is there any color or odor? Are there any special requirements for cleaning toilets or handling odors?

The filtering and disinfecting processes used by Water Harvesting Solutions eliminates any odor or color in the greywater delivered to toilets. Our process produces a treated water quality that does not require additional cleaning or odor handling systems.

Does Wahaso offer services for organic (passive) processing of rainwater and stormwater like green roofs and vegetated swales?

We believe that building owners should consider passive solutions to handling the rainwater that lands on impervious roofs and parking areas. These methods can often be combined with active harvesting systems as part of a holistic approach to each building project. We consider these options in our consulting phase and can recommend experts in this area for final system design and implementation.

Our community makes reclaimed water (municipally treated sewer water) available for irrigation. Can that water be used to flush toilets in our building?

This is a great idea that should be more common than it is but whether this is allowed depends on the regulations in your community. We can review that option in our Scoping Phase. Reclaimed water often has issues with odor that may be unacceptable for toilet use; a filtering step can be applied to eliminate any remaining odors or colors in the reclaimed water. Local ordinances in your area may regulate the use of reclaimed water to flush toilets.

What is the warranty policy on your systems?

Our installations are warranted for one year after installation.

Does Wahaso provide ongoing system maintenance services?

Yes. Wahaso partners with Chemsearch FE to supply post-warranty services.

What additional operating costs are associated with active systems?

We strive to minimize service and operating costs when we design our systems. We recognize that systems requiring regular interaction with the staff on site increases the risk that the system maintenance will lapse and eventually fail.  We use self-cleaning filters and low maintenance ultraviolet (UV) sanitation whenever possible. 

We communicate with clients during the Scoping process the level of maintenance required so there are no surprises.  A simple system may cost less than $200 per year to operate and maintain.  More complex greywater systems – especially those with high GPM and PSI output – may require $1,000 per year or more for consumables and component replacement.

What is the typical payback for a Water Harvesting system? Do they make economic sense?

System payback depends on a number of factors including the type of system installed (and its cost), the overall efficiency of the system (total gallons saved per year for the capital investment), the cost of municipal water (now and in the future), the local fees for water discharged into the waste system, environmental impact fees for storm water management, etc.

Payback is only one of many considerations for installing a water harvesting system. This can range from as little as one year to 12 years or more depending on your circumstances. Most clients also have broader interests in supporting sustainability of potable water for their area; water harvesting is usually one of several actions taken by clients in an overall environmentally sensitive building. We communicate the efficiency and annual dollar savings through water reuse early in the scoping process so clients can quickly gauge the total value of a proposed system.

What geographic area does Wahaso serve?

Wahaso serves clients throughout the U.S. and Canada. Most of our scoping and development stages can be handled remotely, and we can arrange to come to your offices or work site on more complicated systems. In our model, we pre-build and fully test our systems at our Crystal Lake, IL facility and then disassemble the skids to ship to your location. Our system fees include on-site days for start-up and training. In some areas, we work with local partners to install and service systems.

What funding opportunities are there for harvesting systems?

We are hearing more about grants and other funding resources all the time for projects that reduce water use or reduce the impact of stormwater on the watershed. Please check to see if any grants are available in your area.

What does “Wahaso” mean?

Wahaso is an abbreviation for Water Harvesting Solutions.