Soak-away systems designed for safe disposal of smaller volumes of liquid waste into the ground.
Soak-away systems designed for safe disposal of small to larger volumes of liquid waste into the ground.
Working Principle:
The working principle of a leach pit is similar to that of a soak pit, with one key difference: the pit is not filled with any filter media. It is an unlined or partially lined circular pit designed to allow used water to infiltrate directly into the surrounding soil.
The structure is typically constructed using brick masonry or pre-cast concrete rings. Unlike a soak pit, which contains rubble or brick bats to aid filtration, the leach pit remains empty, allowing for increased hydraulic retention time—particularly useful when managing higher volumes of used water. This design facilitates gradual percolation of the water into the soil.
A removable top cover must be provided to enable periodic inspection and maintenance. To improve system performance and reduce the risk of clogging, it is recommended that settling tank be used as a pre-treatment step before water enters the pit.
Suitability:
Leach pits are primarily used for the disposal of used water, particularly greywater from households or from drain endpoints where the volume is relatively high (up to 10 KLD). They are suitable in areas where the soil has good infiltration capacity, and the groundwater table is low (at least 1.5 meters below the bottom of the soak pit).
They are not suitable for: Flood-prone areas, Clayey or rocky soils, Soils with low permeability
Pros/Cons:
Pros: Can be built and repaired with locally available materials, Low capital costs; low operating costs, small land requirements
Cons: May negatively affect soil and groundwater properties as it does not provide adequate treatment, and the pit will quickly clog.
O&M requirement:
Over time, fine particles, silt, or biomass may accumulate within the pit or around its infiltration surfaces, leading to reduced percolation efficiency. Periodic inspection is recommended, and the pit should be cleaned or desilted every 2–3 years, or sooner if overflow or surface pooling is observed in the surrounding area.
|
Parameter |
Design Value |
Unit |
Remarks |
|---|---|---|---|
|
Hydraulic retention time |
2 |
Days |
assumed |
|
GWT below leach pit below slab |
min 2 |
m |
assumed |
India’s rural sanitation sector has witnessed significant progress under the Swachh Bharat Mission Grameen (SBM-G), with increasing emphasis on sustaining Open Defecation Free (ODF) outcomes and strengthening Solid and Liquid Waste Management (SLWM) systems across villages. As rural communities continue to evolve and generate higher volumes of greywater and wastewater, there is a growing need for decentralized, cost-effective, and sustainable rural used water management solutions that are technically sound and easy to implement.
Despite the availability of various treatment technologies and management approaches, Gram Panchayats, Rural Development Departments, and implementation agencies often face challenges in selecting appropriate technologies, preparing technical designs, estimating costs, and planning site-specific interventions. The lack of standardized technical resources and easy access to implementation-ready designs further slows down the execution of rural sanitation infrastructure.
To address these challenges and support the effective implementation of rural used water management systems, WASH Institute has developed this dedicated web-based Rural Used Water Management Portal. The portal is envisioned as a comprehensive technical decision-support platform to assist states, districts, blocks, Gram Panchayats, and practitioners in planning and implementing sustainable rural sanitation infrastructure.
The portal provides a curated repository of commonly adopted rural treatment technologies and management systems, including soak pits, leach pits, waste stabilization ponds, DEWATS, drain-end treatment systems, co-treatment models, FSTPs and other decentralized greywater management solutions suitable for rural contexts. Each technology package includes standard design drawings, technical specifications, implementation guidance, and quantity estimates (BoQs) that can be readily adapted for field implementation.
The technical resources available on the portal have been prepared by experienced sector experts in alignment with CPHEEO guidelines, SBM-G operational guidelines, and established field practices. The technologies featured on the portal have been successfully implemented across multiple villages and states, ensuring their practicality, scalability, and suitability for diverse rural conditions.
By making standardized designs and implementation resources easily accessible, the portal aims to strengthen planning capacities, reduce duplication of technical efforts, improve the quality of infrastructure implementation, and accelerate the adoption of safe and sustainable rural used water management systems across India.
Importantly, the portal is designed as a dynamic and evolving knowledge platform rather than a static repository. It will continue to expand through contributions from sector practitioners, government departments, and technical institutions. Future enhancements will include state-specific schedule of rates, GIS-based planning support, case studies, operation and maintenance guidance, and real-time cost estimation tools to further support rural sanitation planning and implementation.
Local governments follow staged planning for grey water management projects — planning and project formulation, DPR preparation, tendering, construction, and operation & maintenance. This portal supports the tendering stage by providing standardized technical drawings and cost estimates.
The designs, drawings, and bills of quantities (BoQs) provided on this portal are intended for reference purposes only and cannot be used directly for construction. Validate design assumptions, adopt locally applicable Schedule of Rates, and ensure compliance with applicable national or state-level standards.