Granny Flat - Easements and Setbacks

I am looking at purchasing a property which I plan to eventually build a granny flat on it. A 2 bedroom 60m2 brick veneer one that I plan to build through the SEPP 10 day approval process (block is more than 450m2 and wider than 12m).

The property has a slight slope to the rear. It has a sewer easement which is going diagonally across the backyard, cutting the yard in half.

1. How would I be able to best confirm the exact location of this sewer, or is the current 'guesstimate' enough? (Dial before you dig plan from Sydney Water, Sewerage Diagram from contract). Is there anything better to order from Sydney Water ?

2. How do I know how deep the sewer is?

3. The block is just under 14m wide, how much would it roughly cost to encase the sewer? Would it be more than 10k? Would it need fully encasing or only on the part that the GF got too close?

4. Is it possible to build a granny flat with less than 3m rear setback? I do see some structures in the street built closer than 3m rear, but most are older garages been there for a long time. If I wanted to go this path would I need to lodge a DA with council for the GF build? It is zoned R2 in Strathfield Council. This would allow me to stay further away from the sewer and make better use of the backyard. I can't seem to find any info on secondary dwellings in the DCP though.

5. What are the likely costs of this build? I was thinking budgeting 120k including fencing and landscaping.

Attached is some relevant info. The GF satellite photo plan the GF is actually 66m2 so 6m2 needs removing. This was because I changed it to an L shape design.

 

If you contact SYD Water they will advise which 3rd party organisation you can contact for exact measurements - typically a large plumbing company like Reece.

They will tell you.

Depending on depth maybe even $20K? You need to stay away from the "zone of influence" of the sewer line.

NOT as a CD (complying development - 10 day PC)

Yes

Look here: NSW Legislation

$120-130K + sewer encasement.

 

Drainage diagram available from Reece for $30. IIf you are keen, you can pay $550 for a pegout survey. That is the only way to accurately get the info you need, for pipe position , construction and depth.

No greater than 1k per metre to encase replace.( machine access). Did this 6 months ago, in water charged sand.

Keep in mind you'll need to pier if in ZOI. Need an allowance for this

 

Thanks for the replies.

This is the link to the SEPP. I am trying to find in the council planning instruments where it refers to the rules surrounding secondary dwellings (granny flat) being approved via the council rather than the SEPP (as I will want to try and get an approval for less than a 3m setback). I have looked at the LEP and DCP from Strathfield Council. So far the LEP says R2 zoning permits secondary dwellings (if approved). The DCP mentions nothing about secondary dwellings.

Is this different to the diagrams I can purchase from Sydney Water? I already got the free Dial before you dig diagram, would having these paid diagrams add value?

When looking at plans, how do I tell whether they are sewer or drainage?

How big machines are needed for encasement? There is a small carport that a bobcat could get under but if it is a larger thing, it's going to be tight.

How much extra to construction costs would be created due to going close to the sewer? E.g. if I remain 60cm away from it..what allowance would you make?

Thanks !

 

Note to self: when is Strathfield being merged?

 

How big machines are needed for encasement? There is a small carport that a bobcat could get under but if it is a larger thing, it's going to be tight.

It'll be fine with that access and height restriction.

How much extra to construction costs would be created due to going close to the sewer? E.g. if I remain 60cm away from it..what allowance would you make?

You need to get invert level of pipe, soil class so you star quantifying these things. This will determine zoi.

If you own the site, draft a drawing that you want. All these problems can be solved. With a pegout report your engineer can design you a detail for pricing. Drawings can be amended if un palletable , engineer can advise. I used a third party to get my doc set through Sydney water. Good luck. Get researching on Sydney water requirements.

 

You have enough plans there and unlikely get any more. It's enough to get within a metre

Stick your head over the fence to 44 look for a sewer cap. Then look over the fence down steam and look for the fence intersection and find the mh lid. Connect the dots and that's where it runs.
You can use the mh as a guide how how far off the back fence the sewer is

The "1.6" is how deep the sewer is at the mh hole. At the end of the line the "1.0" is 1m deep at the end of the line. Again connect the dots and the lay of the land will tell you how deep but likely 1.5 at fence up to 1.3 upstream fence.

 

It's only shallow so you could get a 5t excavator in no worries

 

Thanks for the info everyone. Given there is only 2 properties north of this subject property benefiting from the sewer pipe, (#46 and #44), is it plausible to consider relocating the pipe? Would that mean putting like a 90 degree type elbow on it as soon as it went into my subject property block and then re-routing it down right near the back fence, and then routing it back? Or would I need to negotiate with all the land owners (#44, 46 and 59) then dig up their backyards (and replace/make good IF they agreed) in order to achieve this?

Would it save money/hassle compared to encasing? Or better to just leave it where it is (I dont even know if moving it is actually allowed/an option) and encase it and be done with it?

 

NO.

Id say you wouldnt be able to given the depths of the pipe. the reason they ran it on an angle to begin with is to service those blocks, moving it to the back fence probably wouldnt get the fall from the house to sewer main connection point.

unless the neighbours are wanting to granny flat as well then you could all split the cost. but i doubt you would have much chance getting it through sydney water. doesnt hurt to ask though