Purpose of water storage tanks with pump?

[carolyn]

We have a villa on VDM and just inside the bounday where the mains water enters the property, are three tanks sunk into the ground that contain water. The mains pipe feeds these and then an adjacent pump (in a little 'house' complete with tiled roof!) pumps the water (uphill) to the villa. The tanks are leaking because of plants roots pentrating them, and our manager has suggested bypassing these tanks, but none of of us is sure if they serve a real purpose? For example, would the mains pressure be too high for the villa pipework if the tank/pump system was removed? Anyone out there any ideas? The villa is a typical Edgar de Lagos build from about 30 years ago.

[Mexican Pete]

Carolyn, I think the answer may be that back in the 80s the water supply was far less reliable than it is today and the purpose of your tanks was probably to ensue that there was always a supply for the house. Get a plumber to rig a temporary bypass and slowly increase the pressure if you’re worried about the pipe work in the house.

[laserblazer]

It's not storage for the irrigation system is it?

[sam]

We have a similar set up, but only one tank. It is a back up supply. We bought our property 16 years ago, and in the distant past needed to use the pump a few times. One of days we will get around to bypassing and removing it.

[steve]

In the 1980's the mains water supply was quite unreliable and was often cut off. It was possible to go several days without mains water and so house were built with cisternas to provide reserve water supplies. These could be very large concrete structures which held many thousand litres or fibreglass tanks holding 500 or 1000 litres. A float valve controlled the entry of mains water and a pressure pump connected the cisterna to the house. When the mains water went off the pressure sensor in the pump cut in and the pump automatically supplied water to the house.

I don't think that many modern house still have this feature. Ours has it only to ensure that there is a good supply of water for irrigation. Most of the old pumps are probably not working now. The hole to the pressure switch silts up and the baloon in the sphere loses pressure. Since water is seldom off for more than a few hours now the reserve tanks are not really necessary and could be disconnected if necessary.

[Gambrinus]

Do not underestimate the deterioration of the infrastructure in some areas of the council. Last year alone we had at least a dozen cases of ruptured mains, where the repair work warranted switching off zones for a day or two.
My guess is it will not be getting any better in the future, as the pipes are not getting any younger. With the crisis reducing the funds to Lagoa council, there is not much left in the kitty to invest in renewing anything. (zero € in 2010 from the regional improvement plan fund).

Even if you only use it to provide sufficient pressure for the irrigation, a backup water supply is always a good thing to have, just in case. Just don't forget to split the system, so the irrigation does not end up using the emergency water when the mains do cut out.

[martin]

you could also catch rainwater from guttering and divert into the tanks which would help a little to irrigate your garden


cin paints in lagoa do (well did) a special paint for cistern's which seals then

[Globetrotter]

Even if you only use it to provide sufficient pressure for the irrigation, a backup water supply is always a good thing to have, just in case. Just don't forget to split the system, so the irrigation does not end up using the emergency water when the mains do cut out.

If anyone is interested in a system like this, we have one for sale. 2 1000 ltr tanks and the pump. EUR200 for the entire set up and the tanks are rated for potable water.

[carolyn]

Thanks for all your replies. We will try and decide what to do when we are over later this week. A paint that seals the tanks sounds interesting - so will investigate that. Also the thought that Portugal being one of the PIGS countries is likely to continue having the sort of problems Gambrinus has mentioned. One day we'll come out to CVO for a visit without having a problem to resolve