Site Suitability Assessment (SSA)
Site Suitability Assessments
Our practice has a qualified Percolation & Water Table Test Operative on staff as these tests are now required to be submitted with all planning applications.
When specifying a site specific wastewater treatment system there are many factors to consider, it is our job to find a practical, cost-effective solution that protects both the drinking water supply and the surrounding environment. Our practice will refer to the current EPA Code of Practice 2021, S.R. 66:2015, and the latest Building Regulations Technical Guidance Document H to ensure compliance with current regulations & requirements.
The purpose of an EPA Site Suitability Assessment is to determine the suitability of the site for a wastewater treatment system. The assessment will also help to predict the wastewater flow through the subsoil and into the sub-surface materials. The site characterisation process outlined here is applicable to the development of a single house and more extensive site characterisation is required for cluster and large-scale developments.
The key to installing a reliable on-site system that minimises the potential for pollution is to select and design a suitable treatment system following a thorough site assessment. For a subsoil to be effective as a medium for treating wastewater, it should retain the wastewater for a sufficient length of time, and it should be largely unsaturated and hence aerated. Only after a site assessment has been completed can an on-site system be chosen.
The information collected in the evaluation will be used to select the on-site system.
In designing a wastewater treatment system to treat and dispose of the wastewater, three factors should be considered:
Are there any site restrictions on the site?
Is the site suitable to treat the wastewater? (Attenuation)
Is the site able to dispose of the wastewater? (Hydraulic load)
To assess the factors a site characterisation is undertaken.
1. A Desk Study; and, if there are no site restrictions,
2. An On-site Evaluation, consisting of:
A Visual Assessment;
A Trial Hole; and
3. Conclusion and Recommendation (selection and design of a wastewater treatment system).
To assist in the selection of the on-site system and to standardise the assessment process, a site characterisation form should be completed. The completed form including photographs, site plans, cross sections and design details should accompany all planning applications for on-site wastewater treatment systems for single houses.