# Forum Home Renovation Landscaping, Gardening & Outdoors  AHD and RL - how to find

## gsouth

Totally off topic I know - and I apologise if what I am asking makes no sense - it's the first time I've been asked for this information on a DA.....  
I am submitting plans for a pool and council have requested heights to be RL using AHD. 
How can I determine the AHD of my datum point? Can I do this myself (I have access to some equipment through a friend)  or do I need to get a surveyor in? 
Hoping there is someone out there that can shed some light..... 
Geoff

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## boban

Determining the Reduced Level (RL) of your existing site is not that difficult if you have a reasonable understanding of mathematics.  
AHD is the Australian Height Datum. There will be a AHD reference point in your street somewhere (generally a kerb). The Department of Lands in NSW will have details of where you can find the reference point. 
Now if I were you and didn't want to call in a surveyor I would take a reference point off your gutter at the boundary and refer to it as 100.00. Then take your levels in the area you need to survey and mark the RL's. For example if the point is 1220mm higher than the reference point (the gutter) then it is recorded as 101.22. The council basically want to know how you are going to change the level of the land and the level of the finished product whether it be a roof, fence, wall etc. 
A surveyor will do it for about $400 BTW.

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## Sir Stinkalot

Perfect sence .... 
AHD - Australian Height Datum 
It is generally the case that you have a land surveyor establish the AHD. There is some sort of data base that will list the AHD levels in your area. Once a surveyor has established a new point it will be added. 
If you look on the footpath of recent developments in the area you will often see a rivet in the footpath which is either a relative level or a AHD point. If you can find a AHD point, and its value, you can then take points from this back to your property to find your own AHD levels. Depending on how far this point is will help determine if you would bother with it yourself ..... you could be taking levels all over the neighbourhood. 
AHD levels are generally required for town planning applications and relative levels only for building permits. 
If the council requests that you get a re-establishment survey .... if you are close to the boundary this needs to be done and signed off by a licenced surveyor ($1000). 
Hope this helps.

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## gsouth

Thanks everyone - none of the developments in the street required AHD unfortunately.
We just had the surveyors out here making sure the boundaries were correct so we could have asked for worse timing. 
There's a point they used in the street but it has no data on it.... to find the data apparently I can do that online inquiry at a cost.... 
Might be better to just simply go with getting a surveyor in.... 
Thanks
Geoff

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## echnidna

Council records should show your nearest height datum points and their AHD

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## Sir Stinkalot

> Thanks everyone - none of the developments in the street required AHD unfortunately.
> We just had the surveyors out here making sure the boundaries were correct so we could have asked for worse timing. 
> There's a point they used in the street but it has no data on it.... to find the data apparently I can do that online inquiry at a cost.... 
> Might be better to just simply go with getting a surveyor in.... 
> Thanks
> Geoff

  The point for the re-establishment survey may just be the boundary markers.

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