Sewer and sanitary drainage
Building sanitary plumbing and drainage designed so waste leaves the building cleanly, with falls, vents and fixtures resolved before construction.
Services
Hydraulic design for buildings
Compliant, coordinated and constructable documentation across sewer, water, stormwater and roof drainage, gas, trade waste and wet fire. Building hydraulics only.
OTG designs the hydraulic services inside and on the building so the set can be coordinated, certified and built. We do not substitute for architecture, structure or fire engineering. Each engagement is scoped to the services you actually need.
Water services
Potable cold and hot water, including storage, boosting and metering where the building needs them, coordinated with plant space and architecture.
Stormwater and roof drainage
Roof, balcony and building stormwater hydraulics: gutters, downpipes, overflow and internal rainwater pipework sized and documented for the building.
Gas services
Natural gas and LPG pipework for building services, from meter to appliance, documented for installers and for certification.
Trade waste
Pre-treatment and drainage for commercial kitchens, laboratories and process areas so discharge can meet the water utility's requirements.
Wet fire services
Hydrants, hose reels and sprinkler pipework as hydraulic design, coordinated with the rest of the building services. Not a substitute for fire engineering.
How an engagement typically runs
01
Brief
Drawings, programme, authority constraints and the hydraulic services in scope.
02
Fee proposal
A clear scope, exclusions and programme. Premium consultancy, scoped to the job.
03
Design and coordination
Calculations, layouts and documentation resolved against the rest of the building.
04
Issue and support
For-construction documentation, with practical support when questions come from site.
Next step
Request a fee proposal
Send the drawings, the programme and the hydraulic services in scope. We will come back with a clear proposal.