OSSM Wastewater assessments in Wollondilly | Southern Wastewater Consulting

Wastewater assessments and OSSM reports in Wollondilly Shire Council and South West Sydney

Property owners, builders and architects across Wollondilly Shire and South West Sydney will need a wastewater report when building or upgrading on land that isn’t connected to the sewer network.

Southern Wastewater Consulting helps our clients progress their DA by providing council-ready assessments that examine how wastewater can be safely treated and managed on the project site.

Southern Wastewater Consulting provide quick turnarounds, high quality, and cost-effective reports, while working in consultation with our clients and the environmental constraints of the site.

Much of Wollondilly LGA is made up of large lots and remoote lots where reliable on-site sewage systems are essential. We visit your site to test and then analyse your soil, slope and environmental constraints to determine the most appropriate system—ensuring it meets Wollondilly Shire Council’s On-Site Sewage Management (OSSM) requirements and operates effectively long-term.

We prepare wastewater reports for:

New dwellings, rural homes, studios and granny flats
System replacements, relocations and upgrades
Subdivision and boundary adjustment proposals
Commercial and tourism developments such as cafés, wineries, wedding venues, farm stays, schools.

Every assessment is written to comply with Council's requirements. Your report will contain:

Detailed site and soil testing
A wastewater system sized and designed specifically for your land
A scaled site plan showing irrigation or disposal areas, buffers and setback distances
Clear guidance on suitable system types, including septic systems, aerated wastewater treatment systems (AWTS), composting systems, greywater reuse, absorption and irrigation solutions

We also deliver land capability assessments. For subdivision projects, a land capability assessment is a critical early step. It confirms that a site can realistically support on-site wastewater management and helps avoid lot layouts that won’t meet council requirements later

Effluent testing and system performance checks

For existing systems, we offer wastewater and effluent testing across the Wollondilly region. Tests measure nitrogen, phosphorus, E. coli, BOD and other indicators to confirm whether a system is performing safely and in line with Council expectations. Results are explained in straightforward language so you know exactly what’s working—and what may need attention.

Experienced, local and focused on compliance

With more than 15 years in wastewater design, soil science, geology and regulatory compliance, we understand exactly what Wollondilly Shire Council looks for in OSSM assessments. Our goal is to deliver documentation that is practical, technically sound and ready for submission without delays.

Areas we service in the Wollondilly Shire

Picton, Tahmoor, Thirlmere, Buxton, Couridjah, Bargo, Yanderra, Wilton, Bingara Gorge, Menangle, Menangle Park, Douglas Park, Appin, Pheasants Nest, Cawdor, Razorback, Orangeville, Belimbla Park, Glenmore, Werombi, The Oaks, Oakdale, Mowbray Park, Lakesland, Mount Hunter, Mount Hercules, Mount Murray, Silverdale, Warragamba, Wallacia, Nattai, Yerranderie, Burragorang, Avon Dam region, Cataract, Nepean Gorge localities, Werombi Common, Stonequarry, Myrtle Creek, Picton Lakes developments, Bargo River localities, Maldon, Tahmoor West, Picton North.

We also work across the broader South West Sydney growth corridor and surrounding peri-urban and rural-residential areas where properties are often not connected to sewer, including parts of Camden, Campbelltown and the Macarthur region.

This includes areas such as Cobbitty, Bringelly, Rossmore, Leppington, Oran Park, Gregory Hills, Gledswood Hills, Catherine Field, Harrington Park, Mount Annan, Currans Hill, Elderslie, Narellan, Narellan Vale, Smeaton Grange, Denham Court, Austral, Badgerys Creek, Luddenham and Kemps Creek.

We also service the fringes of the Blue Mountains and Hawkesbury where on-site wastewater systems are common, including Mulgoa, Wallacia surrounds, Castlereagh, Londonderry and parts of the lower Mountains.

Southern Wastewater Consulting makes the wastewater reporting process simple, fast and compliant—so your development can move ahead with confidence.

We'd love to help on your next project. info@southernwastewater.com.au or 0435 575 403.

Our three step method

Email Info: A site plan or early layout can help, but it’s not essential. We’ll let you know exactly what we need so everything stays straightforward.
After Quote: Once the quote is accepted, we’ll visit your property to assess the site and soil, then send you a preliminary plan for wastewater disposal for consultation.
Final Report: Once you've endorsed it, we’ll prepare the final report in 10-15 working days. You’ll need to provide your local Council with your wastewater report.