Connect Water Pump Directly To Mains Pipe?

[CaptainSplod]

Hi Folks!

We have a problem with low pressure water coming from the mains. That's to say the

pressure is mostly ok during the day, but in the evenings the pressure is way too low.

I can imagine it's quite a "popular" problem in many parts of the country, along with

powerouts, internet connections and all the other things. We live in a very small

village out in the burbs.

I'm thinking of buying a small water pump to maintain a steady flow, but being a

complete novice (read: idiot!) at this sort of thing, I'm hoping that you more

intelligent and experienced guys can help out with some good advice.

Really, it all boils down to just wanting to take the evening shower. We don't

need a whole bunch of fancy installations and gadgets all over the place, but

just want to keep things as simple as possible. We're talking about using a pump

for around 15 minutes a day, that's all.

Checked with the Thai neighbor - they don't have a water pump but use

something they call (in Thai) a "dye naam", which I gather is a 'dynamo',

though what it looks like and how it operates is anybody's guess, as the

neighbor only makes use of the contraption. It was apparently already there

when he bought the land some years back. Maybe some of you guys know

what this thing is.

Here's some info on what we have :

Half inch standard Thai water pipe coming in from the mains, to the

one-storey house, which also has half inch pipes.

The pipes are all visible i.e on the ground and on the outside house-walls - none

under the house - and no hidden or buried pipes.

No water tank - and would preferably not want to have one, either.

One bathroom with toilet, bum-hose, sink and shower (with water heater).

One outside tap.

Later, we're planning on adding another (likewise) bathroom and

one more outside tap - which all in all ain't a great deal. We don't

actually use a whole lot of water, either, and try to save where

possible. Yeah, I'm 'green' in more ways than one!

To me, the "normal" setup is to have a tank connected to the mains,

then have a water pump installed between the tank and the house.

BUT -

1. Can I attach a pump directly to the mains, without having any problem?

2. Seeing as this is mostly an "evening" problem, I don't really

need to to have the pump turned on during the day - and certainly

not during the night - but will I still get the normal mains water

pressure in the house, with the pump turned off or in a powerout?

3. Any recommendations as what brand/type of pump I should

use - and cost? Seem to remember that standard size for inlet

and outlet pipes on a pump is one inch - is that so?

4. Just out of interest, do pumps have a "reverse" switch, so

that water can be pumped the other way?

5. Anything I should avoid or be careful of?

Sure hoping you guys can help out - and thanks for your time!

PS 'Scuse me putting this post here, ain't sure where it ought

to go - thanks.

Splod

[Mossfinn]

Have a look in D.I.Y

Go to the bottom of the page and key word pumps, a whole range of topics appear, there might be something helpful there.

Edited November 4, 2009 by Mossfinn

[Crossy]

In most countries it is illegal to pump from the mains, that said it is common practice here.

The issue is that without check valves you could pump crud from someone elses bath / pond into the main and thence to your taps. Better to install a holding tank filled from normal mains pressure and pump from that.

Moving this to DIY.

[stgrhe]

I agree with Crossby that you should install a holding tank before the pump. However, in order to achieve a good flow of water you need not only consider the pressure but also the flow and your half inch pipes are indeed a limiting factor. These thin pipes will limit the amount of water that you can pump into your house irrespectively of the pressure, but since your requirement is moderate I do not see that it will matter in your case.

[katabeachbum]

I agree with Crossby that you should install a holding tank before the pump. However, in order to achieve a good flow of water you need not only consider the pressure but also the flow and your half inch pipes are indeed a limiting factor. These thin pipes will limit the amount of water that you can pump into your house irrespectively of the pressure, but since your requirement is moderate I do not see that it will matter in your case.

Basicly you are competing with your neighbors to get water. The lowest positioned tank gets most of the water.

[longball53098]

Install the tank. It should be as stated between the mains supply and the house. Pump only from the tank when mains supply is low or off. The pipes and valves should be connected in such a way as to provide water from the mains when the supply is good and when the supply pressure is low the pump will automatically give you water from the tank. No need to switch on the pump manually. Also check valves are places to prevent any back flow to the mains supply and tank.

[lopburi3]

Please use a tank - I do not see anyone pumping direct anymore here in Bangkok but not sure if that is for legal reasons or not - but it is a danger to you and others if you start to bring septic water into the mains leaks by having them go negative pressure.

I would just use the pump as it gives the chlorine in water a chance to breath out and makes for better taste. Also less plumbing. But would include a tank/pump bypass option in even pump fails/tank needs cleaning and such. Another advantage of tank is you will have water during short outages.

[Crossy]

Your pump setup should look something like this:-

The non-return valve ensures that the city supply provides water when its pressure is high enough that the pump is not needed, it also ensures a water supply when the power is off or the pump out of service.

[CaptainSplod]

Just managed to read the first coupla replies before having to work

the rest of the day.

Look in the DIY link - thanks - I'll see what I can turn up!

Ain't a good idea to connect directly to the mains. Yeah, get your

point, though will have to look up "check valve" to see what that

little puppy does.

Appreciate for the info so far - and will get back to other replies

Splod

[Crossy]

A 'check valve' is UK plumber speak for a non-return valve.

Unfortunately nothing you do will prevent the possibility of drawing ground water into the main through one of the (doubtless many) leaks.

Get the tank, you know it makes sense

[longball53098]

Another term for "check valve" is "backflow preventer"

[lopburi3]

That is a new one on me. Wiki lists four terms as below - must admit have never heard it called "clack valve" either - your backflow preventer at least makes sense in my American English.

A check valve, clack valve, non-return valve or one-way valve is a mechanical device, a valve, which normally allows fluid (liquid or gas) to flow through it in only one direction.

[mdechgan]

Use a tank,

1) You don't suck the water from the entire community for yourself.

2) Sucking water from the main will make your water meter spin like crazy. The inertia of the meter sometimes spins more than the water you actually use.

3) You will maintain a steady supply of water to your pump.

[longball53098]

My use of the term "back flow preventer" comes from my MS Visio with a small rectangle diagram and "BFP" in the center of the box. The shape is described as a backflow preventer . Don't know what Google or Wiki says

[CaptainSplod]

Whoa! - seems to be an awful lot of equipment is needed for just

a few minutes good supply of water! But really appreciate all your

comments!

Yep - the pressure falls a whole deal in the evening, reckon the locals

return home from work and wash, make food, fill up their water tanks(?)

and hence the decrease in pressure. Looks like most places have the

half inch pipes (from what we can see) - we ain't planning on getting a

bathtub, jacuzzi or anything fancy and the water system otherwise works

reasonably well (at least for the moment!).

This is a pretty small and 'simple' area with many people using open

concrete water tanks to store their household water - outside bathrooms and

that sorta thing. Ain't really nothing modern anywhere, no ponds in people's

gardens, no drains, no bathtubs (I'm guessing) or modern septic tanks and all

grey waste water usually goes directly out to the kitchen garden, 'cept for the

toilet, which is connected to a sunken concrete ring tank. The main point

here is that you get water piped to your land, but there are no return pipes

or drainage of any sort - all water is "in", none "out". Getting someone else's

crud is maybe nigh impossible, save perhaps with a broken mains pipe.

Hey, Crossy - thanks for the neat diagram, too - very informative.

Anybody know what the "dye naam" thing is?

Lastly - any takes on questions 3 and 4?

Thanks, guys

Splod

[PhilHarries]

Why not just install an elevated header tank? It fills up during the day, need a float valve as per Crossy's flow diagram, and you drain down from it at night. No need for a pump nor a non return valve, although probably a good idea to have one anyway (In the UK the stop valve just inside your house doubles as an NRV).

This, of course, assumes you live in a house not a 20th floor condo but your post gives the impression of ground floor living.

[JAS21]

I re-piped mine..the builder didn't do a good job..and in addition I have automatic garden watering system. In the photo the supply is the verticle pipe, near the wall, coming upm through the tiles, just to the right of Pump (brown cover). You can see the check valve (nrv) or whatever you want to call it. The supply to the house is the pipe going into the tiles just to trhe rear of the leaf..the left pipe, not the one with the valve.

I actually used two check valves to prevent the pump pumping water back into the company mains.

If you want anymore info PM me....but use a tank....When you buy the pump make sure it's one like mine...it's best to have around 2bar pressure. We are lucky with mains water pressure and normally I have the pump switched off.. If you want to use 'an open' concrete tank..fine..the ball float valve will be feeding the concrete tank whereas I have a steel tank...it is best to cover the tank though..you never know what will fall into it!!

I forgot to mention..in Crossys drawing it shows a pressure tank...my type of pump has it built in. I think he just showed it so you know one is needed.

Edited November 6, 2009 by John45

[lopburi3]

Getting someone else's

crud is maybe nigh impossible, save perhaps with a broken mains pipe.

Not true - your neighbor has a place to wash dirty dishs with a hose into the water and the tap on to fill the container - if there is low pressure you can start pulling that water into the mains. The mains themselves will have entry point if pressure goes negative and there is crud everywhere as septic tanks have to drain excess and that is not something you want in your water system.

If just for shower they do have some Panasonic types with a small pump to make the water feel stronger or pulse that you might be able to use.

[Artisi]

- but it is a danger to you and others if you start to bring septic water into the mains leaks by having them go negative pressure.

I would like to comment further on this statement regarding contaminated water gaining access into the drinking water supply. This is an inherent problem in most 3rd world countries and although rare can also happen in highly developed countries. Fresh water mains can go under negative pressure for a number of reasons and if poorly installed / old / leaking mains are in close proximity to foul ground water then infiltration into the mains can take place.

It follows that if you are pumping on the mains of not you can end up with foul water in your domestic system - the reason why tap water, although it might well be pure ex the water treatment works can be contaminated by the time it reaches your premises - which as far as I am concerned is why tap water is undrinkable in Thailand without further treatment.

[CaptainSplod]

Guess that clears up the check valve thing...

Regarding "sucking water from the entire community...".

Ha ha! Man, that's gotta be one helluva pump to do that - and for

one shower head! Maybe you missed the sentence "We're talking

about using a pump for around 15 minutes a day, that's all".

Likewise, I already mentioned that the normal idea is to use a

tank and then install a pump between tank and house. I don't

have any problem with a "normal" installation - but just trying to

ascertain if there are other alternatives. If there ain't, then

there ain't - but I sure ain't gonna find out, unless I ask. But

whatever, I'm getting some good input from your comments.

Hey, guys, I repeat - we don't actually use a lot of water. Looking

at the bills, we're using around 7 (seven) units (cubic metres) - a month,

sometimes more, sometimes less.

Thanks

Splod

[CaptainSplod]

Sorry about the delay in replying...internet connection problems.

Above (I hope!) is the reply I was gonna send before - in the meantime more

comments have arrived.

The overhead tank sounds like a real smart idea, though I'd be wary about

setting such a tank up - unless it's a small affair, the weight must be

pretty colossal when the tank is full. I did actually mull over such a

contraption before your comment arrived, but ain't sure it's possible

to get hold of a say, max 50 liter tank - even smaller would do the job

nicely. Anyone seen such a tank?

John45 - that's a great looking (and big!) setup you got and many thanks

for the photo and info - very useful.

We got just the one pipe - an "L" shaped one coming from the mains to the

house - no pump, no tank, no nuttin' - but hey, it generally works nicely!

No maintenance or repairs - which is just as well, as there's no repair

guy - 'cept myself.

We don't have an open concrete tank - and no way I'm going to have

one, either.

The risk of neighbor's crud may be a common thing in parts of Bangkok and

other large or flat places, but around this way we got hills and mountains and

not a great deal of people.

The reservoir where our water is tapped from, is halfway up a mountain. As I

previously said, getting someone else's crud is nigh impossible - but that's in

these parts, I wouldn't know about other areas.

Thanks

Splod

[longball53098]

If the system supplies water to the public via a common piping system then I would think crud entering the system is possible whether the system is in the mountains or in the city. Any leak anywhere has the possibility of allowing crud into the system when the pressure is down. You don't know what the neighbors are doing with their pumps if they have them.

It sounds like you live a simple, trouble free life there and just as you say allow a few minutes a day to enjoy a shower or two. A small tank say 500 liters and a small pump and some plumbing items will not set you back more than about 5 or 6 thousand baht if you don't buy the best stuff. You will have a nice shower when ever you want.

[Beardog]

Captain you could opt for a small water tank check valve & use a manually operated irrigation style pump for about 1200 baht. Pump when water pressure is good & store in the tank. You really need a tank even a small one to suffice the amount of water you use in the poor water hours. We had the same problem when we lived in Pattaya. You definitely want a check valve so your neighbors cant snag your water you have saved. And if you don't have a tank you will cringe when you see what is coming out of the mains. Our tank bit the big one & our owner we rented from expected me to pay for a new one so I just cut the tank out & every now & then the Pattaya spewage would pound through the shower& leave a nice residue on us & the shower area. We Moved 1&1/2 months later. good luck .looks like on the slim 7000 baht for the remedy. Pending if you can't be bothered by turning the pump on for 20 minutes or not. If you go with a manual pump even with a float valve in the water tank you need to turn off the pump(or install a timer) or it will pump till it burns out & make you hate your electric bill.

[CaptainSplod]

Okay! Y'all got me over a barrel, so guess I'll use a tank - and I don't have

a problem with that (just in case some people might think so). Was hoping

for some easier alternatives, but apparently there aren't any. It ain't

no big deal. Reckon I'll get all the necessaries next month (hey! a sorta

Christmas present - now that ain't bad at all, is it!).

As is pointed out, crud happens, or is gonna happen at some time in the

future, whether it's from a neighbor or not.

longball - I heartily agree with you. Leaks (and breaks) can allow crud into

the system. And yes, we (try to) live a trouble free life, thanks - at least we

did until I started this thread (only kidding!).

The irrigation pump idea (from Beardog) sounds cute - got any info as to what

it's about, cos I don't know what it is (maybe the same as the "dye naam"

thing?). Oh, and I stayed in Pattaya for a while, myself, in my opinion the

so-called water system in that town generally sucks - so know just how you

felt. Yeah, and I cringed more than a few times, too!

Back on topic -

Presuming that I've got a tank and a pump - there are just a coupla things

left to know - primarily the ins and outs (pun intended) of the pump.

Excuse my dumbass questions, but never had a pump before, so know

nothing about the way they're built or their workings.

From previous experience, many things one buys don't come with a manual in

this country - or if they do, then it's in Thai or some kind of strange English

that I've never learned.

Most pumps seem to have a standard one inch in/outlet, probably the more

correct terms are suction- and discharge pipes. I don't know if the pump

in/outlet pipes have threads (for screwing) or are smooth (for glueing).

What do I have to buy to connect half inch pipes to one inch in/outlets?

More important, anyone know the Thai words for what's needed - that would be more

than appreciated.

Any need for any special electrical work ? I see on the photo that john45 kindly

provided, that the cord is connected to something behind an enormous leaf.

Is that a standard cord (cable) that comes with the pump?

I remember seeing a chart a long time ago, showing the size of pump needed,

relative to house size - anybody know where I can see that chart?

More later -

Thanks

Splod

[longball53098]

I won't go in to detail here but all of the stuff you mentioned is readily available at any "local" hardware shop. I don't recall where you live but you must be close to a bigger town.

The pumps come fitted with a plug but usually not the third pin for grounding so a wire to a ground rod will be needed.

Yes the pumps have 1 inch screw in input and and output ports. A tank in the size you will buy also has the 1 inch inlets and outlets. The shops sell screw in fittings for this. You will need some 1 inch PVC and some reducers from 1 inch to 1/2 inch and some half inch pipe. The back flow preventers in a half inch size. A instruction booklet comes with the pump and a diagram of suggested hookups is in the book. I'm sure several folks will give you a diagram on the how to as well as step by step instructions if needed.

If this is a DIY project then tools to cut the PVC and clean the joints is needed as well as some channel lock pliers or spanners and plenty of teflon tape for the screw in fittings.

Can someone else pick up on this list and see what I missed here?

And maybe a simple diagram for his needs?

[Crossy]

Diagram in post 8

I think LB got most of the requirements, don't forget PVC cement (and a means of applying it) and you'll need a lot more PTFE tape than you could imagine.

Ensure that your threaded adaptor arrangement can be screwed (and importantly unscrewed) without rotating the plastic pipe. I replaced a pump for a friend about 12 months ago, unfortunately the installer had screwed adaptors into the pump and then glued these to the PVC, nett result, we had to cut the PVC to get the pump out

[longball53098]

I was just doing some reading about landscape irrigation and came across this explanation for using back flow prevention in a home watering system. I think if you read this it can be applied to any watering system here in LOS

Backflow Prevention

[Cuban]

Regarding "sucking water from the entire community...".

Ha ha! Man, that's gotta be one helluva pump to do that ....

Sorry I'm late with this comment, but FWIW, I don't think anyone else mentioned the situation when the mains supply goes off. For whatever reason the supplying mains pumps ceases to provide positive pressure in the system so your pump would easily suck off the entire village - so to speak. You can't know what arrangements exist in other peoples houses. It is very common (our house included) to leave a tap just cracked open to allow a trickle of water refill larger holding tanks, if someone has the idea of reducing the dripping noise by placing a short length of hose over the tap and into the water - your introduction of negative mains pressure would suck out their water. Or if there is a weakness in the piping infrastructure as others have said take in ground water.

I estimate we have about four days heavy water usage in storage reserve in case of main failure, worst I have encountered is one complete day with no incoming supply due to local pump failure.

[bkkbill]

This is the union I use right at the pump only blue in color

[CaptainSplod]

Thanks for the info on the in- and out pump pipes. Had already imagined

that they'd be the screw type - but ya never know!

Now that I've got some time to plan where to put the tank, pump and pipes,

make drawings of the system - and to note how many elbows, t-sections, valves

and other things are needed.

One thing would be nice to know - if there's no power to the pump (or it fails),

can water still flow from the tank and thru the pump to the house, so that I still

get a weaker flow of water (for emergency use) ?

I rather doubt it - and it ain't no big deal to throw in an extra length of pipe to

bypass the pump, if that's what's needed.

Thanks

Splod