Over 10 years, a traditional concrete septic tank keeps costing money in repeat gully bowser visits and repairs, while a mechanical STP adds ongoing electricity and motor servicing costs. Parawewa Option A has no electricity cost and no routine gully bowser fees, so the gap in total cost tends to widen the longer the property is owned, backed by a 10-Year written warranty.
The upfront price of a Parawewa tank is typically higher than a basic concrete pit — but a fair comparison has to look past the installation quote to the full cost of ownership. Below is a realistic 10-year financial breakdown framework for a typical 5-person residential property in the Colombo / Gampaha area, alongside how the same logic scales up for developer and commercial sites.
Residential 10-Year Breakdown (5-Person Household)
- Initial Tank Installation: A one-time capital investment, covered by a 10-Year written warranty from Parawewa.
- Operational Savings: No routine gully bowser call-outs, and no added electricity cost under Option A.
- Net 10-Year Position: The avoided recurring costs commonly exceed the price premium over a traditional pit within the first few years, after which the system is effectively saving money for the remaining warranty period.
A housing scheme development in Bokundara illustrates how this math changes at developer scale: fitting every unit with a gully-bowser-free system removes a recurring maintenance line item that would otherwise fall on either the developer's service charge or individual homeowners for the life of the scheme. The same logic applies to commercial-scale sites like Commercial Credit's premises in Kiribathgoda, where predictable, low-maintenance facilities costs matter for long-term budgeting.
Why the Comparison Widens Over Time
A traditional concrete pit's costs are recurring and, in many cases, increase over time as the structure ages and requires more frequent servicing or eventual reconstruction. A mechanical STP adds a second recurring cost layer — electricity — on top of its own servicing needs. Parawewa's Option A removes both recurring categories from the equation for the life of the 10-Year warranty, which is why the total cost gap tends to widen the longer the property is owned, rather than narrow.
