Key takeaways
- Recycle Ready fitout for an apartment complex with 36 apartments (excluding grey water recycling unit) costs about €1,214 per appartement. Only about €428 more than a traditionally piped apartment complex.
- Recycle Ready fitout for a terraced house (excluding grey water recycling unit) costs about €1,497. Only about €460 more than a traditionally piped terraced house.
- Recycle Ready fitout for a semi-detached house (excluding grey water recycling unit) costs about €2,418. Only about €1,190 more than a traditionally piped terraced house.
- A Recycle Ready building will be more valuable than a traditional building.
- With the International Construction Costs 2024 report from Arcadis, you can calculate the Recycle Ready costs in your city.
- Two Recycle Ready proposed projects show the difference in extra pipework depending on the type of project.
Executive Summary
This white paper explores the costs and benefits of preparing buildings for grey water recycling through a “Recycle Ready” fit-out. Grey water, which originates from showers, baths, and washing machines, can be treated and reused for non-hygienic purposes such as toilet flushing and garden irrigation, offering significant reductions in water usage. The analysis covers three building types: apartment complexes, terraced houses, and semi-detached houses.
Cost Impact The additional cost of a Recycle Ready fit-out compared to traditional plumbing is relatively modest. For example, the cost increase for an apartment complex is approximately 15% (€428 more per apartment), for a terraced house 31% (€460 more), and for a semi-detached house 51% (€1,190 more).
Water Savings Grey water recycling can reduce household water consumption by up to 45%, depending on the residents’ behavior. For an apartment complex, this translates to savings of over 1.34 million liters of drinking water annually.
Environmental Benefits Grey water recycling significantly reduces the demand for drinking water, and in turn, decreases wastewater production.
Economic Advantage Recycle Ready buildings are expected to increase in value, following trends seen in the energy sector, where energy-efficient homes command higher prices. Furthermore, as grey water recycling becomes more prevalent, properties already fitted with such systems will likely see a long-term increase in value.
Futureproofing The expectation is that water reuse and recycling will follow a similar development path to decentralized energy systems like solar power. Early investment in grey water recycling infrastructure will likely yield financial and environmental benefits as water management regulations tighten globally.
While the initial investment for a Recycle Ready building is higher, the potential savings in water usage, the reduction in wastewater output, and the likely increase in property value make it a sound financial and environmental decision for the future.
Introduction
In this white paper, we explore the costs and benefits of installing a grey water recycling system in three types of buildings: an apartment complex, a terraced house, and a semi-detached house. These buildings are considered typical, making the data scalable. The study uses theoretical models specifically created for this analysis. All underlying data and calculations can be requested from Hydraloop. The white paper is based on calculations with data from the Netherlands, conducted on behalf of the Expertgroup Circulair Water, which is part of Water Europe.
Grey water or lightly polluted wastewater, originating from showers, baths, and washing machines, can be treated, and reused for non-hygienic applications such as toilet flushing, washing machines, and garden irrigation. This reduces the demand for drinking water and lowers the ecological footprint of households. Grey water reuse can contribute to drinking water savings of up to 45%, depending on specific applications and resident behavior (1).
Cost analysis
Apartment complex
Installation costs
The grey water system in an apartment building requires the following installation components:
– household water reticulation and grey wastewater drainage inside apartments;
– collective distribution network for household water;
– collective grey wastewater system, vented and draining to recycling unit(s);
– grey water recycling system.
Below is an overview of the costs:
– Recycle Ready pipework per appartement: €927.62 (€33,394.32 for 36 appartements)
– Collective grey water and household water pipework for the building: €10,331.88
– Grey water recycling system: €55.000,00
– Total investment (Recycle Ready and grey water recycling system): €98,726.20
Recycle Ready costs per apartment
The afore-mentioned costs reflect the total investment to install a fully operational grey water recycling system in an apartment complex. For comparison, the Recycle Ready price per apartment is:
Recycle Ready per apartment excluding grey water recycling system: €1,214.62
Recycle Ready per apartment including grey water recycling system: €2,742.39
| Traditional | Recycle Ready | Percentual difference | |
| Pipework per apartment | €785.80 | €927.62 | 15% |
| Total apartment pipework (36 apt.) | €28,288.80 | €33,394.32 | 15% |
| Collective grey water/household water pipework | €0 | €10,331.88 | n.a. |
| Total (excl. grey water recycling system) | €28,288.80 | €43,726.20 | n.a. |
| Grey water recycling system | €0 | €55,000* | n.a. |
| Total | €28,288.80 | €98,726.208* | n.a. |
*Dependent on the number of devices needed and the local partner and consumer price. Request an updated price from Hydraloop.
Demographic data
The case study is based on a hypothetical apartment complex with 36 apartments, each inhabited by an average of 2.12 people. This means the building houses 76 residents, significantly impacting the total water savings achievable by the grey water recycling system (1).
Water savings
Traditional system: 128 liters (about 33.81 gal) per person per day
With grey water recycling: 80 liters (about 21.13 gal) per person per day
Annual total drinking water savings: 1,348,310 liters (depending on resident behavior)
Annual total wastewater savings: 1,348,310 liters (depending on resident behavior) (1)
Terraced house
Installation costs
For a terraced house, the costs of installing a grey water recycling system are as follows:
– Recycle Ready: €1,497.18
– Grey water recycling system: €3,280.00
– Total investment (including Recycle Ready and grey water recycling system): €4,777.18
Recycle Ready Costs for a terraced house
Recycle Ready excluding grey water recycling system: €1,497.18
Recycle Ready including grey water recycling system: €4,777.18
| Traditional | Recycle Ready | Percentual difference | |
| Pipework per house | €1,036.98 | €1,497.18 | 31% |
| Grey water recycling system | €0 | €3,280.00* | n.a. |
| Total | €1,036.98 | €4,777.18* | n.a. |
*Dependent on the local partner and consumer price. Request an updated price from Hydraloop.
Water savings
Traditional system: 128 liters (about 33.81 gal) per person per day
With grey water recycling: 80 liters (about 21.13 gal) per person per day
Annual drinking water savings: 17,703 liters (about 4676.64 gal) per person (depending on resident behavior)
Annual wastewater savings: 17,703 liters (about 4676.64 gal) per person (depending on resident behavior) (1)
Semi-Detached House
Installation costs
For a semi-detached house, the costs of installing a grey water recycling system are as follows:
– Recycle Ready: €2,418.32
– Grey water recycling system: €4,500.00
– Total investment (including Recycle Ready and grey water recycling system): €6,918.32
Recycle Ready costs for a semi-detached house
Recycle Ready excluding grey water recycling system: €2,418.32
Recycle Ready including grey water recycling system: €6,918.32
| Traditional | Recycle Ready | Percentual difference | |
| Pipework per house | €1.,227.46 | €2,418.32 | 51% |
| Grey water recycling system | €0 | €4,500.00* | n.a. |
| Total | €1,227.46 | €6,918.32* | n.a. |
*Dependent on the local partner and consumer price. Request an updated price from Hydraloop.
Water savings
Traditional system: 128 liters (about 33.81 gal) per person per day
With grey water recycling: 80 liters (about 21.13 gal) per person per day
Annual drinking water savings: 17,703 liters (about 4676.64 gal) per person (depending on resident behavior)
Annual wastewater savings: 17,703 liters (about 4676.64 gal) per person (depending on resident behavior) (1)
Added value of grey water recycling
Grey water reuse not only drastically reduces the use of precious drinking water and reduces the wastewater flow, but it also increases the value of the building. A recent study by the NVM (The Dutch Cooperative Association of Real Estate Agents and Appraisers) shows that houses that are not energy-efficient are significantly less valuable. With an average of 113 square meters, an A-label house is worth €434,900. – The same house with a G-label is worth €365,700. – The price difference between energy-efficient houses with labels A and G is €69,200. – or 16%.
Peter Fiske, founder, and Executive Director of the National Alliance of Water Innovation (NAWI), foresees a water transition, like the one we are seeing with energy, as presented during the 2023 UN water week in New York, USA (3). NAWI has received $110M funding from the U.S. Department of Energy to research how to dramatically lower the cost and energy of desalination and water reuse through a 5-year program of early-stage applied research (4). Traditionally, we generated our energy centrally (per city of municipality) and transported it to individual households. Nowadays, a mix of central and decentral energy use and storage is common. With solar panels and batteries, a large part of the household’s energy use is decentral generated, stored and used.
The expectation is that we will see a similar development with water. A mix of central and decentral generation, storage and use will become common on a global scale and in some places is already common. In Spain, Chili, Florida, and Hawaii there are already regulations in place making it obligatory to prepare a building Recycle Ready or incentivizing grey water recycling. Based on this expectation we can conclude that the investment to make a building Recycle Ready will be financially beneficial. For every type of building outlined above, the investment in making the building Recycle Ready will result in a higher property value (5).
Regional cost variations
This case study is based on data from the Netherlands. Installation costs vary from one country to another. To calculate a Recycle Ready estimate for your city you can use the International Construction Costs 2024 report from Arcadis. Base location index is Amsterdam with 100 points. You can only consider the construction costs. The price for grey water recycling devices does not change in price according to the International Construction Costs 2024 report. (6).
How to calculate an estimate for building Recycle Ready in your city?
Step 1: Transfer the amount in euros to your local currency.
Step 2: Search for the nearest city to you in the index.
Step 3: Multiply the amount with the corresponding index divided by 100.
Recycle Ready use cases
In Gibraltar, a proposed 189 apartment Elderly Care Home is constructed. 126 apartments will be connected to the grey water piping network to purge the grey water from the showers and AC units to 10 x H600 devices. The grey water will be cleaned and reused for the launderette for all residents of the building. In this case, the values are presented in meters of piping.
| Traditional (meters) | Recycle Ready (meters) | Percentual difference | |
| Total pipework | 1.436,02 | 1.620,30 | 13% |
A second proposed project where the difference in pipework has been calculated, is for a proposed 16 room boutique hotel also in Gibraltar. The grey water from three showers and three AC (air-conditioning) units will be collected, cleaned, and reused for topping up the hotel pools, garden irrigation and cleaning of the external courtyards. Due to space availability and budget reasons only 1 x H600 will be installed.
| Traditional (meters) | Recycle Ready (meters) | Percentual difference | |
| Total pipework | 78,00 | 122,50 | 44% |
As shown, depending on the location of the grey water devices, the size and shape of the building and the number of rooms connected, the amount of extra pipework can vary a lot. It is therefore important to include plans for grey water recycling as soon as possible to reduce the amount of extra piping needed.
Conclusion
Installing a grey water recycling system offers both environmental benefits, compared to traditional drinking water generation and distribution, as well as long-term financial savings (7). While the initial investment costs can be a burden, the additional costs per unit are low compared to the potential savings in drinking water use and wastewater production. For apartment complexes, terraced houses, and semi-detached houses, implementing such systems proves to be a valuable step toward more sustainable water management and lower operational costs. Furthermore, the added value of preparing a building Recycle Ready will be an investment for the future when grey water recycling will become the norm. Future proofing your building now will turn out to be a great investment in the coming decades.
References
- Expert Group Circular Water (2024)
- Hydraloop (2024), retrieved from https://www.hydraloop.com
- NAWI (2024), retrieved from https://www.youtube.com/watch?v=7dYHX-Tssqc
- Peter Fiske (2024), retrieved from https://profiles.lbl.gov/31851-peter-fiske
- NVM (2024), retrieved from https://www.nvm.nl/media/w3xm2oy0/bijlage-4-energielabels-op-de-woningmarkt-themaonderzoek-bij-nvm-kwartaalcijfers-2024-1.pdf
- Global Construction Costs Report (2024), retrieved from https://www.arcadis.com/en/knowledge-hub/perspectives/global/international-construction-costs-2024
- S. Canizales, Ecocosts LCA Water Recycled via Hydraloop H300 v1.5 (2024)