This is an archival version of the original KnowledgePoint website.

Interactive features have been disabled and some pages and links have been removed.

Visit the new KnowledgePoint website at


water quality Levels in hospital


New bore hole drilled in Feb '11 to provide water supply to rural mission hospital. Dubious water quality; fluoride 15 and advised install reverse osmosis plant - too expensive an option especially a there are high sodium levels. Driller has inserted a pump to enable water to be elevated to a tank on top of tower 44mts away. Not yet connected to the pipes which lead to the tank and the bore hole has been uncapped & leaking into the locality for 3 weeks. This has flooded 5 septic tanks in the hospital and flooding is apparent over the surrounding area. Public Health Dept have closed hospital. Driller believes if he connects pump it will solve the problem and take the water away. We are advised that the bore hole is not going to provide potable water; the pump should be removed and the pipe sealed and capped.

The advice will be used by personnel who are unqualified to be dealing with the sort of problems we are encountering. Project raised in US. On- site supervison by local Rotary personnel, who are being led by the driller's opinion. Hospital is at Kilimambogo, nr Thika and as volunteers we run a dental clinic in this hospital and stay involved with community affairs.

Very sketchy outline above but need an opinion. Have requested an urgent independent water analysis from bore hole before anything further happens. If someone is able to help - advice would be hugely valued.

Regards Janice

5 Answers


Some thoughts from one of our Technical Experts to consider - suggestion is to abandon well.

Assuming fluoride concentration is mg/l and with high sodium this is unfit and would cause fluorosis if consumed for periods. Definitely out for hospital use Sounds like aquifer connected in some way to a hydrothermal plumbing system of a volcanic region or from soda lake! The only way really is RO which has been ruled out not surprisingly. The other method is distillation if a big enough solar furnace available! Again huge expense. One wonders about geological surveys in the area - any available to indicate source of fluoride and sodium? Otherwise, if levels remain high then cap the well as no good for anything really - the fluoride at that level will probably cause crop problems too if used for irrigation. Could use this water though for toilet flushing and washing etc. provided safeguards in place to prevent drinking, and mixing of this with potable water. Recommend not for boilers/autoclaves though as it will corrode them to hell and back. One last thing - high sodium and fluoride indicate this water could be very aggressive to metals (corrosion) so care needed in capping off the well or any conveying pipework/pumps/valves etc.

regards phill

Harriette Purchas

Dear Janice,

There was another recent RedR TSS enquiry on fluoride in water. The basic advice was that that this sort of pollution is usually localized and if it does not dissipate with pumping then you are better off looking elsewhere for water as treatment is too complex/expensive. I would agree that you do not want to look at reverse osmosis which is an expensive option both to install and to operate.

Looking at the map you are on the edge of the rift valley with all the complex igneous geology that goes with it. It appears from the Internet that there is abundant groundwater in the area so it may be possible to drill more successfully nearby.

Drillers may be good at drilling and may have an intimate knowledge of local groundwater conditions but they are not generally trained in water chemistry or treatment. There must be a local office of the Ministry of Water Resources Management and Development (MWRMD) who can give advice though they are probably under resourced.

I was a bit confused by all the flooding that has taken place when the pump has not yet been connected and assumed that you must have drilled into an artesian aquifer (water coming out under pressure). Depending on the water pressure and the relative elevations of the borehole and the tank you may not even need a pump to get the water to the tank. If the water is un-usable, however, you are better off taking out the pump to use elsewhere and capping the borehole. If the groundwater pressure is really high then it will simply keep overflowing from the top of the tank rather than from the top of the borehole unless it is closed off with some sort of valve. There would be little point in keeping a tank filled with water that you cannot use.

I hope that this helps.

Best regards



Thank you for your replies. This last piece of information from Martin is very helpful - appears spot on and is in line with our way of thinking - that our bore hole will never produce potable water. We received a Water Treatment Equipment Proposal from Davis Shirtliff where in their discussion, suggest that as the well pressure exceeds that of the ground pressure, assistance from a pump will not be required. Borehole yield: 40m3/hr - estimate. The bore hole was drilled in February. A test pump was installed at 68 mts. and water flowed for 24hrs before the pump was removed - flashing and capping were completed. The report suggests the water pressure was high after the pump was removed. The bore hole remained capped until mid-June, when the drillers said there would be insufficient pressure to elevate the water and that a pump would be necessary to get the water from the bore to the tank. The drillers returned and inserted an submersible pump into the system around June 15th. Because there was no 3-phase electrical connection available, it was left disconnected and open - and leaking +++. On July 18th, the driller returned to the site and said it could not be capped because the water would build up too much pressure. It still continues to leak - but we have no clear idea of how great a volume. The consequences are terrible in the staff quarters living in the near vicinity; it is a quagmire of stagnant, smelly water. Their pit latrine has filled with water spillage and also the septic tank. The hospital has been closed by the Kenyan Public Health Dept. The advice from the drillers is to connect the pipes to the pump to take the water to the tower to stem the flooding asap. We have requested new independent water analysis samples and instructed the electrical connection must not be made to implement the system until the poor water quality is verified. (Not certain if water properties change over time/depth? First analysis showed high fluoride at 15. Sodium was only 488mg/l.)

Expectation is that pump should be removed and the bore hole to be abandoned. The driller is yet to be persuaded this will be the course of action. The on-site project manager is a Sister (Roman Catholic nun) who is supported by 2 senior Rotarians from Thika and Nairobi - advice that has been received is mostly from the drillers who wish to see their job completed - blow the consequences. They say the water is good for washing and cleaning. This nightmare scenario is compounded with poor communication about what is happening between all concerned personnel. It is with deep frustration that the situation is not resolving. As volunteers, my husband and I are going out to Kenya in mid-August for 3 weeks to do some dentistry and to give a project overview!!

Thank you for the observations you have made - which concur with the course of action that will be taken - if the new water ... (more)


Dear Jan

I have just looked up the World Health Organisation guidelines for maximum levels of the two chemicals that you mention in drinking water;

• Sodium – 200mg/l (you have 488mg/l so are in excess of the guideline) • Fluoride - 1.5 mg/l (you have 15, you do nor state units but presumably mg/l and are therefore in excess of this guideline)

You will be aware of the debate over the adding of fluoride to water for dental health benefits but the levels involved are generally less than 1.0mg/l and high levels can be toxic.

High sodium levels would have implications for the risk of hypertension, diabetes and chronic kidney diseases.

Best regards


Harriette Purchas

Hello Toby, Thank you, for the enquiry that was made whilst we were working in Kilimambogo, Kenya - this is the reason for my late reply - during the 3 weeks we spent in Kenya, most days, electricity was rationed to about 10hrs. provision in every 24hrs. It played havoc with our communications from the deep rural area in which we live and meant that very few emails were able to be sent or received.

This message is to say how much we valued the information and technical support that was received from RedR TSS in response to my enquiries, prior to our return to the area where the borehole problems are being experienced at Kilimambogo, Thika District, Kenya. From August 14th until last week, my husband and I were working in Kilimambogo ; much of our time was been spent in dealing with the complexities of the uncontrolled discharge from the borehole , which to date, still continues to leak because of inappropriate capping measures. The high water pressure has resulted in the capping breaking down. There was no wellhead construction.

The drilling company, had failed to recognize that the drilled borehole was into an artesian supply. This is a very unusual situation in Kenya. Had artesian conditions been anticipated, appropriate methods would have been deployed to prevent problems before they occurred. The drilling contractor knows that uncontrolled artesian flow is not allowed in Kenya and that he should have advised that the water needed treatment before it use. Had an hydro geologist been employed to oversee the project from the outset, (who would have been employed at significant cost,) many of the outcomes would not have come to pass.

The Kilimambogo Borehole Installation project has been fortunate in securing the services of an experienced hydro geologist, Mike Lane - Aquasearch Ltd, has identified the difficulties of this "problem borehole" and made recommendations as to how it should be dealt with. Mike is advising that the bore hole be "shut in and abandoned", since the water analysis indicates high quantities of both fluoride and sodium being present. The contaminants would be difficult and costly to remove - what ever system is employed. There would also be a matter of corrosive water damaging, and ultimately destroying galvanised iron pipework - the most commonly used material in the supply of potable water in Kenya.

In summary, the fact that the borehole was a "problem borehole" exposed weaknesses in on-site management and quite possibly, the contract processes would not have occurred had the borehole been more typical of Nairobi aquifer system boreholes. Currently, the project leads are waiting for proposals and costs to be provided by the drilling company. The drilling company appear not to understand the recommendations and requirements and are dragging their heels about providing the necessary quotation for removing a submersible pump from 68mts. depth and working to a specification laid down by Mike, to reduce the water level in the hole so there is no longer any free discharge; the detailed remedial steps are explained ... (more)