Water pump for well

[Sophon]

The current drought has prompted us to think of alternatives to the village water should matters get worse. So far we have had water every day, sometimes with fairly low water pressure but as we have a storage tank and pump that is not a problem. But who knows what will happen in the future.

Luckily, our land already has an old well. It's not a deep well, only about 4-5 meters deep, but according to village folk lore it never runs dry. It used to be the "village well" and was used by everyone back when the village was (even) smaller and there was no village water supply. The older people in the village also claims that the water from the well is very good and sweet, but that might just be nostalgia talking. At the moment the water table of the well is only about 1.5 meters down (so about 3 m. of usable water).

The question is what kind of pump do I need to pump the water out of the well? As I mentioned, the well is 4-5 meters deep, so I have to be able to suck the water up from that depth. I also have to push the water through about 50 meters of water pipes to reach the house and our water tank. The inlet to the water tank is at a height of around 1.70 meters. Since we already have a constant pressure pump supplying the house from the tank I don't need the water to come out at any particular pressure, basically even a trickle would do as long as I am able to fill up the tank.

I know that pumps are much better at pushing water than sucking it, but if I read the specification tables from the pump manufacturers correctly (and there is a distinct possibility that I don't) a standard pump like this Hitachi WT-PXXXGX2 should do:

Depending on the model number, they should be able to suck water from a depth of 7-8 meters (suction lift) and push it to a height of 12-20 meters (discharge head). Since I only need about 5m/2m suction lift/discharge head, that would seem to be plenty. I don't believe I will need a submersible pump or anything like that.

So now to the specific questions:

1. Assuming I am right about the type of pump I need, what model (wattage) should I choose?
   I am thinking that the Hitachi WT-P150GX2 (or similar Mitsubishi model) should be plenty for my needs.
2. Does the size of the water pipe going down into the well matter?
   The inlet pipe size for the pump is 1", but I am wondering if scaling it down to 0.5" before going down into the well might make it easier to suck the water (less weight of the water) and/or help maintain the vacuum when the pump is not running.
3. Any other tips or things I have to remember to do to make sure the set-up runs smoothly?
4. Questions I haven't thought of yet, but that will no doubt creep up later.

Thanks to everyone in advance for any information you can give me.

Sophon

[Crossy]

That pump should do the trick.

Do NOT reduce the inlet pipe, if anything go bigger, give it a foot valve at the bottom and you'll be good to go.

Although it's a self-priming pump prime it anyway and you'll wait less time for the water to flow.

Your well water will likely be a bit muddy, a coarse crunchy-bits filter between the pump and the tank will keep the big bits out.

[Sophon]

That pump should do the trick.

Do NOT reduce the inlet pipe, if anything go bigger, give it a foot valve at the bottom and you'll be good to go.

Although it's a self-priming pump prime it anyway and you'll wait less time for the water to flow.

Your well water will likely be a bit muddy, a coarse crunchy-bits filter between the pump and the tank will keep the big bits out.

Thanks Crossy.

I will keep the 1" pipe all the way down the well then, and add the foot valve at the bottom (I have seen those at Global House before). I think the water is relatively clean, we have layers of laterite below the ground which I guess might help with filtering the water (but might also make the water rich in iron?). I'm sure there are still some sediment in the water, so I will look for a particle filter as you suggest but I have looked for such a filter before without any luck. Mostly what I find are the carbon and resin filters to remove chemicals and calcium and some very small particle filters that I don't think are sufficient. Do you have any particle filter brand/model (and place you can purchase it) that you can recommend? What do you have yourself, if you don't mind me asking?

Since you were the one replying to my post, I have an electrical follow up question. I will have to lead an electrical cable to the pump to supply the power to run it. It's only about 30-40 meters from our house, so I was thinking that 2.5 sq.mm. copper NYY cable buried in the ground in a conduit should be OK. Am I correct in that assumption, and if so do you know where I can buy this cable? I bought the 16 sq.mm. NYY cable for our house at Global House, but I haven't seen any smaller size NYY cable there (but I haven't asked either, so they might have it).

Thanks again.

Sophon

[In the jungle]

Crossy is right.

Do not go smaller on the suction pipe and, if anything, go bigger. Use a footer valve.

I use agricultural water filters. Around 100 Baht each for one inch. You can clean them so you do not have an ongoing maintenance cost. They are fairly coarse filters which have pros and cons.

The pro is maintenance is minimal and costs nothing.

The con is that they do not get the really small particulates out.

What always puts me off the carbon/osmosis/whatever stuff is the demo always has a pathetic trickle coming out at the end and the salesman is always a charlatan with a smile and shiny pointy shoes. Plus the daft maintenance costs.

I get around the fact that the filters I use do not catch the small stuff by using water storage as settlement tanks. The tanks are drained, flushed, cleaned and steriiised in rotation. 30,000 litres of storage in total for a house that normally only has two people. In the dry season we pull around 3600 litres a day from our well. Most of the water we use goes on the garden.

There are a whole bunch of controls for the system. Most are simple water level switches. The only electronic one is a timer switch to minimise stress on our not terribly productive well.

I use a Mitsu ACH375S as the well pump and the suction head is, currently, 5.87 metres. They work fine and cost around 3K a pop with one Inch inlets and outlets. But they are a throw away pump. If it goes wrong you throw it away and get another one.

I have fancied trying the Hitachi pumps you mention but when you are solely reliant on well pumps, as I am, if the well pump fails you fix the problem fast and the Mitsu pump I mentioned is what I can get quickly.

[Sophon]

Crossy is right.

Do not go smaller on the suction pipe and, if anything, go bigger. Use a footer valve.

I use agricultural water filters. Around 100 Baht each for one inch. You can clean them so you do not have an ongoing maintenance cost. They are fairly coarse filters which have pros and cons.

The pro is maintenance is minimal and costs nothing.

The con is that they do not get the really small particulates out.

What always puts me off the carbon/osmosis/whatever stuff is the demo always has a pathetic trickle coming out at the end and the salesman is always a charlatan with a smile and shiny pointy shoes. Plus the daft maintenance costs.

I get around the fact that the filters I use do not catch the small stuff by using water storage as settlement tanks. The tanks are drained, flushed, cleaned and steriiised in rotation. 30,000 litres of storage in total for a house that normally only has two people. In the dry season we pull around 3600 litres a day from our well. Most of the water we use goes on the garden.

There are a whole bunch of controls for the system. Most are simple water level switches. The only electronic one is a timer switch to minimise stress on our not terribly productive well.

I use a Mitsu ACH375S as the well pump and the suction head is, currently, 5.87 metres. They work fine and cost around 3K a pop with one Inch inlets and outlets. But they are a throw away pump. If it goes wrong you throw it away and get another one.

I have fancied trying the Hitachi pumps you mention but when you are solely reliant on well pumps, as I am, if the well pump fails you fix the problem fast and the Mitsu pump I mentioned is what I can get quickly.

Thank you for your reply.

We only use about 10 units per month, so we will most likely continue using the village water and just have the well as a backup and perhaps for watering the garden. Unless the water situation changes for the worse, we don't plan on building extra storage beyond the 1,000 litre water tank we currently have. Because of this changing from one supply to the other will be done with manual stop valves.

I am not familiar with the agricultural filters you mention, could you expand a little on what they look like and where you buy them? If possible, a picture would also be very nice so I know what to look for.

Thanks again.

Sophon

[In the jungle]

The filters I use are here:

http://www.itec.co.th/

[Sophon]

I just thought of one more question.

Let's say our well is 4.5 m deep, how deep should the end of the pipe drawing water out of the well go? Obviously, the longer down the pipe go the longer will we be able to get water from the well should we have a severe drought situation, where everything starts to run dry. On the other hand, I would expect the water to be more muddy near the bottom of the well. So what is a good compromise, one meter from the bottom or...?

Thanks again.

Sophon

[bankruatsteve]

Assuming you're not doing yourself... why not go with the driller's experience? How would somebody know your water level situation? The bore hole guys are usually pretty good at that.

Edit: Sorry, just re-read the OP. So, you already have the bore hole/well/whatever. I would still get somebody experienced to install pump.

Edited January 24, 2016 by bankruatsteve

[Sophon]

Assuming you're not doing yourself... why not go with the driller's experience? How would somebody know your water level situation? The bore hole guys are usually pretty good at that.

Edit: Sorry, just re-read the OP. So, you already have the bore hole/well/whatever. I would still get somebody experienced to install pump.

For the same reason I ended up having to install the electrics for the house myself - there are no longer anyone here in the village doing jobs like this and no-one left with the knowledge to do it properly. Everyone is relying on village water now and the few wells still around were dug many years ago and are mostly not used. When we bought the land we didn't even know there was a well here, and didn't find out until we started clearing the land four months later:

Even finding someone to clean out the well and line it with concrete rings and stones/sand turned out to be almost impossible. The only people willing to do it were two guys in their late sixties, one of which turned out to have been one of the people originally digging the well 50 years ago when he was just a teenager:

Sophon

[MaiChai]

Interesting photos. We also observe its getting more difficult in Issan to find skilled folks for reasonable prices. Thus it becomes easier to diy than find someone and pay silly money.

[Sophon]

This is our water straight out of the well without any settling or filtering. Look pretty encouraging and might turn out to be better than the local village water supply, especially at the moment where they have to take water from Mae Tha river to fill up the village water tanks.

Sophon