With over 25 years experience DTS specialise in consent to discharge applications and full drainage surveys for both pre and post house sales. We carry out on-site assessment surveys on existing septic tanks and waste water treatment plants. We offer a comprehensive service from survey to supply and installation often covered via insurance. Unlike dealing with the insurer direct and getting a “settlement” we aim to make sure the adequate funds are available for completion.


A Percolation test is simply observing how quickly a known volume of water dissipates into the subsoil of a hole of known surface area. This test is used to determine the water absorption rate of your ground type in preparation for the building of a wastewater drainage field or percolation area. The results of a percolation test, comprising three test hole results, are required to properly design a waste water treatment system and mandatory for submission of a discharge consent application.


Please fill in as much information as possible. Only contact details are required.


Private/Domestic Property:

Commercial: Yes/No

New build: Yes/No

Government : Yes/No

Is the property off-mains drainage? Yes/No

Is the system septic tank? Yes/No

Is the system a W.W.T.P? Yes/No

Is the system on third party land? Yes/No

Is the system soakaway or direct discharge?

Is there a legal easement in place? Yes/No

Note: If possible, take photos to show issues described above.

Has the WWTP been serviced recently? Yes/No

If served by a soakaway or drainage field has it ever been jetted out in previous 5 years? Yes/No

Note: If the purpose of this enquiry is part of an Insurance claim investigation or validation survey, you must contact NI WATER on 0345 744 0088 to acquire the previous three annual desludge. If possible provide receipts, look for comments or remarks made by previous tanker operators.

Is a site assessment survey required? Yes/No


Development/ New-build: Yes/No

House Sale Drainage Survey: Yes/No

Bespoke Custom Design: Yes/No

Commercial or Public Use: Yes/No

Insurance Claim Survey: Yes/No

Validation Survey: Yes/No

For Private Contract: Yes/No


Is a Vac-tanker required?

Is Jetting Gear required?

Is CCTV & CAT-SCAN required?

Is a mini-excavator required?

Has a percolation Test to be carried out?

Is an outside water tap available?

Has a desktop study been carried out?

Is the property located on or in close proximity to any environmental or historically sensitive zones or areas?

Is the property on a flood risk zone?

Is there a nearby mapped waterway?

Are there large trees close to the property?

If WWTP proposed is there access to power supply?

Is booking for survey confirmed? (please complete below)

Note: If a current NIEA consent or SEPA registration is available. Print off and attaché to this folder. ** Attach two of either OSNI or SEPA maps of the property, one to record the existing system and one to record any new proposal and co-ordinates that may be required.

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