Browse Forums Renovation + Home Improvement 1 Jul 30, 2012 8:46 pm All was supposedly done and dusted with our renno, but a cockup at final inspection and a lazy builder resulted in non-compliant drainage which after some wrangling our builder has agreed to rectify. In a nutshell we need to connect stormwater to existing drainage (at present it drains to a right of way), but how that’s to be done leads me to my question. To avoid digging up/cutting the concrete footpath/kerb crossing our plumber wants to reroute drainage from our downpipes quite a distance (from one side of the house to the other). In the process he wants to install a pit and electric pump to move the water the said distance. Like ⋅ Add a comment ⋅ Pin to Ideaboard ⋅ Crude mudmap I know, all the stormwater is to be routed down the right side of the house to the pit then pumped to the left side and out to the street. …..my question is ….is that how you would do it? I have reservations about the pump…it will require maintenance, electricity charges etc and one day need replacing altogether. If it fails during bad weather we end up with a flooded back yard. Plumbers what do you think??????? Re: Drainage.....Question for plumbers 2Jul 30, 2012 9:18 pm Not a plumber, more electrician, and it's not my idea of a preferred solution! Most of the time if the power goes out its in a storm! It might save a few bucks compared to digging up the driveway and path but it adds complexity (the pump) I wonder if you can have the pit and no pump? Just fill the pit which raises the water enough to go down hill again, still not ideal since the pit won't drain completely, but got to be better than relying on a pump 2 Re: Drainage.....Question for plumbers 3Aug 04, 2012 2:04 am You have not mentioned the roof area, the slope of the land, information the plumber has given you about pump and pit sizes and costs amongst other things. Too many unknowns to give a proper answer but here are a few things to consider. What you describe is a pumped wet well stormwater detention system. Firstly, check with your council re requirements (and what is posted below) as councils often add their own rules. The wet well must have a minimum capacity of 3 m3 and a ladder must be installed if the depth is greater than 1.2 m. High and low level alarms must be installed. Pumps MUST be in duplicate. This is to prevent the requirement for a single high volume pump that would have frequent stop/starts during normal rainfall, an operating condition that causes expensive pump failure. The pumps required combined flow capacity also means expensive pumps. Think a minimum of 600 lpm! What size pump(s) has your plumber mentioned? Pumps must also be controlled so that the number of individual start ups per hour is restricted for the reason stated above. There are also regulations regarding the requirement for surface overflow provision in the event of power/pump failure. This could/would involve additional landscaping. You say that the plumber doesn't want to dig up or cut the concrete footpath/kerb crossing. How will he plumb the discharge from the pump/s to the street if he doesn't do this in any case? stormjr has mentioned possible power failures in storms. Sooner or later, you will have a power failure during a major storm. Many councils do not allow the type of system you describe for this reason. I think you are looking at an expensive 'solution' with a high energy requirement. Why not have onsite detention with say 3 rainwater tanks. If they were linked and if the fall of land provides a suitable head, the tanks could overflow to a 'charged' pipe draining to the street. This way, the money spent on harvesting rainwater would have another practical purpose. If there is negative slope along the pipe draining to the street, there must also be provision for flushing...and somewhere for that water to go. This option obviously still involves a pipe to the street but l still can't see how your plumber would get around this by having a pumped wet well. I would love to know the answer to that! Have you asked him? Detention tanks are usually required to have small overflow pipes plumbed lower on the tank so as to provide reserve detention after the tank fills to the overflow level during a major storm. This is to allow the tank's mitigation reserve to prevent high volumes of water leaving the property at the height of the storm. This overflow pipe size requirement contravenes plumbing regulations. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: Drainage.....Question for plumbers 4Aug 05, 2012 2:04 pm Whohhhhhaaa lots of info there saveh2o...the set up you describe sounds bigger than the desal plant lol. First off this solution is being proposed by our builders plumber and would be the cheapest easiest option available to them.....which of course makes no sense to me. I havnt spoken directly to the plumber but the pit as described to me would be a lot smaller than anything mentioned above. All of the stormwater is to be discharged via an existing pipe on the south (left) boundary which im not sure will cope. Council are involved as they were the ones who picked us up on our existing drainage so the balls in their court as far as approvals. I plan to give the plumber a call on monday to offer an alternative, I cant see why it cant run across the front of the house. This may involves some standing water in part of the undergrounded piping, but im told thats ok for stormwater. Watch this space. Re: Drainage.....Question for plumbers 5Aug 06, 2012 10:56 pm Ok...there is an existing drainage pipe on the south side. It is easy to calculate this pipe's maximum compliant flow rate and this is the first thing that needs to be established. The use of a pumped wet well, even if the water is pumped to an existing drain rather than pumped to the street as I previously understood, would still be subject to the referenced Australian Standards. This is covered in AS 3500 Part 3, Section 9 - Pumped Systems. 9.3.6 states in part: The minimum wet well storage between the high and low working levels expressed in cubic metres shall be 1% of the catchment area in m2 but in any case shall not be less than 3 m3. If your plumber is considering using a small wet well and only one pump, I would be very concerned. Apart from compliance, a large wet well capacity reduces the number of pump start ups per hour. 9.3.7 deals with high and low level alarms. 9.4 deals with the requirement for pumps in duplicate and other associated matters. Ask the council if you can have a look at their current copy of AS 3500.3 Section 9 only covers 2 pages. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Hi HomeOne, I'm in the midst of landscaping a cat run down the side of my house, and the recent rains have me wondering if I need to install some sort of drainage. I've… 0 12275 2 5841 I would find out how deep your clay base is and depending on the depth install a cut off drain which is more than a normal agi drain. Where the neighbouring walls is… 2 3147 |