Sinking A Bore

[Jai Dee]

I've searched this forum for similar topics but haven't found anything.

I am about to start constuction of a new house in the Na Jomtien area.

Observing other works going on in the development, I have noticed that whilst digging for preparation of foundations, the water table is only about 1 - 1.5 metres below the natural surface level. It's surprisingly high given the fact that we haven't had rain in a long time.

As my block of land is about 200 sq wah and will have a large garden area, I am toying with the idea of sinking a bore complete with submersable pump for the sole purpose of watering the garden. Although I will also have a swimming pool I'm not sure about the quality of ground water, so I'd prefer to use the town water supply to keep that topped up.

Has anyone had any experience with this?

Can anyone recommend a company that does this?

[Thetyim]

I have had shallow bore and deep bore made.

You do not need a submersible pump for a shallow bore.

What do you want to know ?

[Jai Dee]

What do you want to know ?

Thanks for the response Thetyim,

As I said, I'm thinking of using bore or well water to water the garden, but want to weigh up the costs before actually embarking... it may be cheaper just to use town water.

The ground water table is only about a metre below the surface. How deep should one go to get reasonably clean water? What sort of arrangement would you recommend? And what would be the indicative costs?

[Thetyim]

We have an 80 meter deep bore which cost 80k baht. But do not expect 1000baht a meter for a 10 meter bore. A submersible pump for this type is expensive 20k upwards.

I would guess that a bore deeper than 30 meters should give you clean water for the pool.

A shallow bore is dug by hand and is usually about 6 meters deep and 80 cm wide.

10k baht should see it dug and lined but you will have dubious water quality. Do not drink it. The pump for this setup is 3000-6000 baht

Town water is the cheapest option but water quality will vary, have chlorine added ( not good for the garden), and of course you will get a monthly bill.

If you value your health and can afford it then go for a deep bore.

Edited March 9, 2005 by Thetyim

[roiet]

What do you want to know ?

<{POST_SNAPBACK}>

Thanks for the response Thetyim,

As I said, I'm thinking of using bore or well water to water the garden, but want to weigh up the costs before actually embarking... it may be cheaper just to use town water.

The ground water table is only about a metre below the surface. How deep should one go to get reasonably clean water? What sort of arrangement would you recommend? And what would be the indicative costs?

<{POST_SNAPBACK}>

30 meters deep could be sufficient for good quality water. But make a 5 day water test at this depth, maybe you have to go deeper. Town water can be very expensive for a pool. About 20 % of the pool water get lost per month due to evaporation and backwash(cleaning)

PS: Do not forget to put your house and pool on 30 cm stilts about 3m down with 4 m2 foundations otherwise you will have a floating house and definetely a cracking pool.

[Jai Dee]

Thanks for the tips guys.

[Thetyim]

About 20 % of the pool water get lost per month due to evaporation and backwash(cleaning)

Our pool is 7 x 11 meters but we only loose a little water.

20 percent sounds very high to me.

[Ajarn]

About 20 % of the pool water get lost per month due to evaporation and backwash(cleaning)

<{POST_SNAPBACK}>

Our pool is 7 x 11 meters but we only loose a little water.

20 percent sounds very high to me.

<{POST_SNAPBACK}>

I lose about an inch a day to evaporation, and figuring in the backwash loss, I'd also estimate water loss from my pool at about 20%....

Speaking of chlorine in the city water, I recently emptied and refilled my pool. Afterwards, when I took the chlorine reading, it was waaay over the level I normally keep my pool at, even approaching a level where I wasn't sure I felt safe swimming. After 2 days, the chlorine was 100% gone... I use this same water in my garden, but haven't seen any problems with plants...

Edited March 10, 2005 by Ajarn

[Thetyim]

I lose about an inch a day to evaporation, and figuring in the backwash loss, I'd also estimate water loss from my pool at about 20%....

OK is it me or you that needs new batteries in the calculator ?

One inch per day means you loose 30 inches per month

If 30 inches is 20percent of your pool then it must have an average depth of 12'6"

Thats a big pool ?

l

[Jai Dee]

Speaking of chlorine in the city water, I recently emptied and refilled my pool. Afterwards, when I took the chlorine reading, it was waaay over the level I normally keep my pool at, even approaching a level where I wasn't sure I felt safe swimming. After 2 days, the chlorine was 100% gone... I use this same water in my garden, but haven't seen any problems with plants...

Sunlight strips the chlorine from your pool water.

Did you use a water supply truck or town water from the mains?

And yes, I think that 20% evaporation does seem like a bit of an overestimation?

[Ajarn]

Speaking of chlorine in the city water, I recently emptied and refilled my pool. Afterwards, when I took the chlorine reading, it was waaay over the level I normally keep my pool at, even approaching a level where I wasn't sure I felt safe swimming. After 2 days, the chlorine was 100% gone... I use this same water in my garden, but haven't seen any problems with plants...

<{POST_SNAPBACK}>

Sunlight strips the chlorine from your pool water.

Did you use a water supply truck or town water from the mains?

And yes, I think that 20% evaporation does seem like a bit of an overestimation?

<{POST_SNAPBACK}>

I used city water, via the garden hose.

OK is it me or you that needs new batteries...

Certainly, my batteries could use a recharge , but I was just thinking off the top of my head...'about' 1 inch per day... And not just from evaporation and backwash as mentioned. That includes some splashover from me when swimming, even without the imagined cannonballs

Now that I think more about it (still no calculator), the loss is more than 20% per month..

My water bill (small household use, watering garden twice per day (about 50 wah of garden space) averages well over 1,000 baht per month.. Last month was 1,600. Each time I refill the pool, I'll see an extra 500 baht in the next month's bill

to fill my about 10,000 gal. pool (not very big)

How do your water bills compare (those of you who get them) ? I remember when my water bills for my house in Bkk were in the 40-60 bpm range a few years ago..

Edited March 10, 2005 by Ajarn

[Jai Dee]

Do you use bore water to top up your pool Thetyim?

[Thetyim]

Yes I use the water from the deep bore

[monty]

I just did a 30m bore and the water I get is close to unusable due to very high iron content. It comes out the pump crystal clear but upon contact with the air it turns brown.

Bring it in contact with chlorine and it immediately turns deep red. Chlorine is an oxidator so it's just the iron being broken down (rust )

The reason of the bore being 30 m is that you normally need an approval to go deeper then that. The dumbass from the bore company didn't tell this to me (to save the cost of the approval) but he(me actually) got unlucky when some local official turned up and inquired to that approval.

So we were stuck at 30m, with absolute unusable water...

If you get a good workin deep well, you'll have water that's much cheaper then company water. About 1 baht/cubic meter it will cost you, taking into account the electricity used, depreciation of the pump etc.

Company water is at least 15 fold, so if you have a big garden and a big waterconsuming swimmingpool your boring cost will be won back many times over...

And the waterflow won't stop at the end of the dry season

[Thetyim]

Whoops, thanks for the heads up on that, Monty

I will shut up now.

JaiDee, PM me if you need more info

[monty]

Ajarn,

You sure the pool is not leaking???

The 20% loss is normal (for an on average 4ft deep pool), but by the amount you're loosing I would guess you have lots of people dashing around in it like madmen

In a 7 by 11 meter pool you would loose around 1 cm/day, and thats with splashing around, evaporation, backwash etc... you loose over double the amount...

If in any doubt, pump it empty and if you see water come up between the tiles you know you have a problem. I had it on a pool, and had to take out all the grout between the tiles and redo it. My water loss dropped from 2 inch per day to 1/4 inch per day (without swimming in it). If a lot of people swim it can loose up to half an inch per day...

[Jai Dee]

I just did a 30m bore and the water I get is close to unusable due to very high iron content. It comes out the pump crystal clear but upon contact with the air it turns brown.

Back in Western Australia I had a similar problem.

I had a reasonably large house block (over 1000 m2) and used a bore coupled with an automatic reticulation system to irrigate the garden. But the water was dirty and brown stains appeared on the paving and fencing where overspray occurred.

Once a month I cleaned it off by painting the stains with a broom in a mix of 30% HCl (Hydrochloric Acid) and water, waiting for 5-10 minutes, then hosing it off. HCl can usually be purchased at pool supply shops. Watch your skin whilst using it though... it burns.

No problems for the grass or plants though.

[Thetyim]

I have done some checking and do not need a license to extract water where I am living.

JaiDee, you will have to check this out for your locality if you decide on a bore.

Monty's figure of 1cm a day loss sounds about right to me

[roiet]

I just did a 30m bore and the water I get is close to unusable due to very high iron content. It comes out the pump crystal clear but upon contact with the air it turns brown.

Bring it in contact with chlorine and it immediately turns deep red. Chlorine is an oxidator so it's just the iron being broken down (rust  )

The reason of the bore being 30 m is that you normally need an approval to go deeper then that. The dumbass from the bore company didn't tell this to me (to save the cost of the approval) but he(me actually) got unlucky when some local official turned up and inquired to that approval.

So we were stuck at 30m, with absolute unusable water...

If you get a good workin deep well, you'll have water that's much cheaper then company water. About 1 baht/cubic meter it will cost you, taking into account the electricity used, depreciation of the pump etc.

Company water is at least 15 fold, so if you have a big garden and a big waterconsuming swimmingpool your boring cost will be won back many times over...

And the waterflow won't stop at the end of the dry season 

<{POST_SNAPBACK}>

I had exactly the same problem with iron content. I store the water in a 3 meter high tank, 1 m diameter filled with gravel 30 % at the bottom. I throw some Soda Ash in the tank and this is washing the water. Twice a day I empty 10 % of the tank at the bottom.

[roiet]

About 20 % of the pool water get lost per month due to evaporation and backwash(cleaning)

<{POST_SNAPBACK}>

Our pool is 7 x 11 meters but we only loose a little water.

20 percent sounds very high to me.

<{POST_SNAPBACK}>

My pool is 8x16x1,6 meters and a 4x4 m children pool. It is 180 m3 . This is a public pool and more than 30 chidren splash at the same time weekends. Total more than 100 splashers on a Saturday. During the week we have an average of 40 visitors per day. I really loose so much water, no crack in the pool, very solid built overflow system.

Because I use borewater I have to make a bit more backwash. And I use also a bit more Chlorine of course.

[Ajarn]

Ajarn,

You sure the pool is not leaking???

The 20% loss is normal (for an on average 4ft deep pool), but by the amount you're loosing I would guess you have lots of people dashing around in it like madmen   

In a 7 by 11 meter pool you would loose around 1 cm/day, and thats with splashing around, evaporation, backwash etc... you loose over double the amount...

If in any doubt, pump it empty and if you see water come up between the tiles you know you have a problem. I had it on a pool, and had to take out all the grout between the tiles and redo it. My water loss dropped from 2 inch per day to  1/4 inch per day (without swimming in it). If a lot of people swim it can loose up to half an inch per day...

<{POST_SNAPBACK}>

Yes, when we emptied the pool a couple of weeks ago for cleaning, we checked for leaks, but saw no signs. Also, we can hear any dripping of excess water into a cistern if there is a slow leak, but no sounds as yet..

I should have added that I have a large 3 meter rock waterfall that will surely add to the loss, plus, the humidity here is lower, and that, coupled with the heat, could mean more loss than in some other more humid areas, I suppose. On a google search, it seemed that 1cm per day in evaporation loss is somewhat typical. Add to that the waterfall and my splashing around a bit, and it seems okay, to me...

Anyway, I never seriously paid really close attention to amounts before, but I will now... I'll see if my guesstimate holds. Thanks for the feedback

[monty]

Jai Dee,

Thanks for the tip about the HCL to clean the walls. I have exactly the same problem on my walls where they get sprayed by the sprinklers...

Roi Et,

I'm having a company coming over on monday who'll show us a filterinstallation.

On the phone they guaranteed they can filter the iron out, after they recieved one liter of sample water I had to send to them...

I'll post the results, might be usefull for other people having these problems.

By he way, this high iron content is in no way harmfull for us, our bodies need a lot of it to transport oxygen throughout our bodies! I'd just prefer to ingest this iron in the form of a cool beer instead of murky brown water

[Ajarn]

Jai Dee,

Thanks for the tip about the HCL to clean the walls. I have exactly the same problem on my walls where they get sprayed by the sprinklers...

Roi Et,

I'm having a company coming over on monday who'll show us  a filterinstallation.

On the phone they guaranteed they can filter the iron out, after they recieved one liter of sample water I had to send to them...

I'll post the results, might be usefull for other people having these problems.

By he way, this high iron content is in no way harmfull for us, our bodies need a lot of it to transport oxygen throughout our bodies! I'd just prefer to ingest this iron in the form of a cool beer instead of murky brown water   

<{POST_SNAPBACK}>

Too much Iron can be problematic.... Here's some info on dealing with Iron in your water and in your body... http://www.dnr.state.wi.us/org/water/dwg/iron.htm

[roiet]

Jai Dee,

Thanks for the tip about the HCL to clean the walls. I have exactly the same problem on my walls where they get sprayed by the sprinklers...

Roi Et,

I'm having a company coming over on monday who'll show us  a filterinstallation.

On the phone they guaranteed they can filter the iron out, after they recieved one liter of sample water I had to send to them...

I'll post the results, might be usefull for other people having these problems.

By he way, this high iron content is in no way harmfull for us, our bodies need a lot of it to transport oxygen throughout our bodies! I'd just prefer to ingest this iron in the form of a cool beer instead of murky brown water    

<{POST_SNAPBACK}>

Too much Iron can be problematic.... Here's some info on dealing with Iron in your water and in your body... http://www.dnr.state.wi.us/org/water/dwg/iron.htm

<{POST_SNAPBACK}>

THANKs Ajarn

Great site. Real helpful information

[roiet]

Jai Dee,

Thanks for the tip about the HCL to clean the walls. I have exactly the same problem on my walls where they get sprayed by the sprinklers...

Roi Et,

I'm having a company coming over on monday who'll show us  a filterinstallation.

On the phone they guaranteed they can filter the iron out, after they recieved one liter of sample water I had to send to them...

I'll post the results, might be usefull for other people having these problems.

By he way, this high iron content is in no way harmfull for us, our bodies need a lot of it to transport oxygen throughout our bodies! I'd just prefer to ingest this iron in the form of a cool beer instead of murky brown water   

<{POST_SNAPBACK}>

Monty

I would be interested to hear the results of your filter testing. I installed lately a manganese/carbon filter to get rid of the remaining iron which I filter trough gravel. I have to do do a lot of backwashing with this filter to get sparkling water needed for my pool and bungalows. Maybe I selected a to small filter, only 100cm high. If I read the recommended website of Ajarn a pure manganese filter could be the solution.

Waiting your results, thanks

[monty]

Roi Et,

the filtersystem the company showed up with was quite fancy. It first injects chlorine, which oxidates the iron when the can easily be filtered out by a regular sand filter.

The whole stuf, pumps, valves, backwash is controlled by a small computer.

Only drawback: 90,000 Baht and it consumes around 5 Baht/cubic meter in chemicals and electricity.

Did you buy manganese/carbon filter in Thailand? if so where and how much?

I know the manganese takes out the iron.

I'll look around a bit more before I commit to an investment this big...

Thanks,

Monty

[roiet]

Roi Et,

the filtersystem the company showed up with was quite fancy. It first injects chlorine, which oxidates the iron when the can easily be filtered out by a regular sand filter.

The whole stuf, pumps, valves, backwash is controlled by a small computer.

Only drawback: 90,000 Baht and it consumes around 5 Baht/cubic meter in chemicals and electricity.

Did you buy manganese/carbon filter in Thailand? if so where and how much?

I know the manganese takes out the iron.

I'll look around a bit more before I commit to an investment this big...

Thanks,

Monty

I bought my filter at Global Roi-et producrd by Mazuma, Bangkok. You can find these filters also at Homepro, Homeworks. My one is stainless steel 35cm diam and 120cm high filled with 33% each Manganese on top, Carbon in the middle and Silica sand at the bottom with manual backwash/rinse. Very effective , I filter 8000 lt per day.The backwash water is dark red. I think more Manganese would be ideal for me because I have very high iron and clay content. Bt 16,000 installed on site including 1hp pump.

[Jai Dee]

Bump!

Great replies and some really useful info so far.

Anyone else out there with any bore/well construction experience?