Borehole cleaning and flushing in Riga and the Riga region

Signs that a borehole needs cleaning

• The pressure drops, the pump runs longer or switches on more often than before, although consumption has not changed.
• The first litres in the morning or after a longer pause are brown or grey, and the filters in the house clog faster.
• Sand or silt appears in the tap strainers or the washing machine filter.
• The water has developed a swampy or hydrogen sulphide smell that was not there before.
• The borehole has not been used for several years and you want to connect it to the house again.

If the water has disappeared completely, the cause is more often the pump, the cable or the controls, not clogging. Then start with the page borehole not giving water. If the smell remains after cleaning too, it comes from the water itself: rotten egg smell in water.

Why a borehole clogs

Groundwater in Latvia often contains a lot of dissolved iron and manganese. Near the filter, where the water flow speeds up and meets oxygen, iron precipitates on the filter slots and pipe walls, and a layer of iron bacteria forms there too. The filter gradually clogs, and water flows in more slowly. In a sandy aquifer fine sand settles in the slots, and in a borehole that is not used for a long time silt builds up at the bottom.

This happens slowly, so there is no strict schedule. Cleaning is planned when the signs appear, or together with a pump replacement, since the pump is lifted out then anyway.

How borehole flushing is done

1. Lifting the pump We lift the pump with the delivery pipe and cable, and inspect the non-return valve, the cable joint and the safety rope. We measure the water level and borehole depth: if the depth is less than in the passport, there are deposits at the bottom.
2. Mechanical cleaning Hard iron deposits are removed from the pipe walls and filter with a brush lowered into the borehole.
3. Flushing with a compressor We lower an air pipe into the borehole, and compressed air from the compressor lifts the water up together with silt and sand (the airlift method). We flush in stages from the bottom up, until the water coming out is clear.
4. Disinfection If the borehole has had bacteria or a smell, it is disinfected with a chlorine solution, left for a set time and then pumped out until the chlorine smell is gone.
5. Pump back and testing We lower the pump back to the right depth, check the pressure and controls, and record how much water the borehole gives after cleaning.

The flushing water is cloudy, and there is a lot of it. In your request, say where it can be led: into a ditch, the far corner of the garden or away from the house foundations. After cleaning and disinfection it is worth testing the water: borehole water testing.

What cleaning will not fix

Flushing removes deposits, but it does not fix a broken pipe, a torn filter or a borehole whose aquifer no longer gives a yield. If sand comes again after flushing, the filter is most likely damaged, and then a borehole repair is needed. Cleaning does not remove iron dissolved in the water itself: that is dealt with in the house by iron removal for a private house.

In old boreholes with rusted-through steel pipes, vigorous flushing can make the damage worse. In that case we first inspect the borehole and tell you whether cleaning is worth it.

How much borehole cleaning costs

Borehole cleaning costs from €400, usually €400–700. The price depends on:

• the borehole depth and diameter;
• how much deposit there is and whether it is hard (iron) or loose (silt, sand);
• whether the pump can be lifted without problems or is stuck;
• whether disinfection is needed;
• access to the borehole head: caisson, adapter or a borehole in a basement.

If during cleaning you decide to replace the pump as well, submersible pump installation costs from €200 excluding the pump price: borehole pump replacement. Other prices: prices.