ᐅ Greywater system – costs and experiences?

Hello, who here has experience with a greywater system?

At the moment, it looks like for our new construction project there are no plans to connect to the sewer system within the next 10-20 years, nor is a small-scale wastewater treatment plant approved, so we have to prepare for the very expensive tank emptying service.

According to my calculations, with only average water consumption, we would easily spend over 100 euros per month just for wastewater disposal... which is why I am considering that a greywater system, which I had previously heard is rarely worthwhile, might actually pay off quickly in our case.

I am grateful for any tips and experiences,

Kaz

Alternatively, consider managing roof drainage through infiltration or soakaway systems.

Thanks, why is that considered an alternative? Our building permit / planning permission includes infiltration, but I would like to collect a good portion for garden irrigation – for which we plan to install a separate meter if we additionally use drinking water. However, this doesn’t affect the amount of water that ends up in our septic tank, does it?

Kazazi schrieb:
... Our building permit / planning permission includes infiltration, but I would like to collect a good portion for garden irrigation - ....

For this purpose, a cistern or well and a pump are needed.
Using greywater makes sense in industrial or commercial buildings. Implementing this economically in a single-family home is unlikely to be feasible in terms of cost-benefit ratio.

Best regards.

€uro schrieb:

Greywater recycling certainly makes sense in industrial or commercial settings. Implementing this economically in a single-family home is hardly feasible when considering the cost-benefit ratio.

What experience is this assessment based on? Realistically, what costs should one expect for a greywater system?

My calculation so far is as follows: the standard wastewater fee for a house connected to the sewer system in Berlin is about 2.50 Euro/m3; the cost for cesspool emptying plus treatment is around 8.50 Euro/m3. With a projected daily usage of 600 liters (about 160 gallons) for our family of five (based on an average consumption of 120 liters (32 gallons) per person per day in Germany), I calculate approximately 220 cubic meters (about 58,000 gallons) per year, resulting in an additional cesspool fee of 1320 Euro annually!

That seems quite significant to me, making payback for such a system not entirely unrealistic. Flushing the toilet accounts for roughly one-third of the water consumption, which translates roughly into a savings potential of about 400 Euro. Is it still not worthwhile?

€uro schrieb:

For this, a cistern or well with a pump.

Why would one of the above options be preferable for rainwater collection over a simple rain barrel for garden irrigation?

Thank you,

Kaz

Kazazi schrieb:
....What costs should one realistically expect for a greywater system?...

As always, this depends on the individual requirements of the specific construction project!

Kazazi schrieb:
....With a projected 600l/day (160 gallons/day) for our family of five (based on an average consumption of 120l/day (32 gallons/day) per person in Germany)....

In most of my plans, the residents leave in the morning and return in the evening. Toilet flushing, lighting, heating, and hot water throughout the day are usually covered by the employer, school, or other institutions.

Kazazi schrieb:
....that a payback period...

Payback periods do not apply to owner-occupied units in principle — basic business administration course!

Best regards.

Forum posts cannot replace comprehensive planning and dimensioning!