Condition of the Large Tank

This photo was taken before the seeping area was patched.

The 127,000 gallon tank is generally in very good shape. It was inspected by the manufacturer, Mount Baker Silo, and a licensed structural engineer who tested the  integrity of the concrete and verified the rebar was installed per spec. There is seepage along many of the joints, which is typical of this type of construction. There is one area about 24′ up on the South side where soil was mixed in with the concrete. Over the years this area has had excessive leakage. Several attempts to patch the inside and outside.

View from inside the tank looking at the layers of patches. (click on the picture for higher resolution)

More pictures of the tank are shown below.

Conclusion and Plan

  1. With routine maintenance we expect several decades of operation from the tank.
  2. Continue to monitor the condition of the tank in general and the known weak areas.
  3. Prepare the small tank for regular operation.
  4. Develop a plan to meet the chlorine contact time (CT) requirements, and have the plan approved by the state dept of health before putting the small tank in operation.
  5. If the seepage increases again:
    1.  Test approved alternate CT plan
    2. Clean and disinfect the small tank
    3. Bring the small tank online
    4. Drain and dry the large tank,
    5. Pressure wash the inside of the large tank
    6. Sand blast the interior areas to be repaired
    7. Roto hammer suspect joints and cracks to enable solid repair
    8. Seal areas of concern
    9. Refill, disinfect and bring back online in an approved manner.

New storage for increased capacity is a different issue, and should be funded primarily by the new members.



These pictures were taken in the spring of 2007 in preparation for repairing the large tank. The plan was to bring the small tank online during the repair process. At the last moment we realized that we did not have a good plan for maintaining the required CT.

The small tank was drained, cleaned, and sanitized.

The small tank prior to draining:

The small tank was surprisingly clean. The water was clear with only a slight collection of dust on the surface. There is some sediment visible in the top left corner of the picture. Mark should be there Wednesday at 9 or 10 to finish draining it, then start cleaning. He wondered if it might have been partially refilled. We will know tomorrow for sure. I don’t see how we could partially fill it without overflowing.

The big tank, looking down at a patch on patch on patch:
  (click on any image to super size it)
This shot was taken while standing on the lid, prior to lowering the level. The electrodes used to control the pumps are dangling on the wires. The hardware holding the breather pipe on the contact culvert is corroded, or has iron deposits.

Here are 3 or 4 different materials used in attempted patches. The wider area epoxy was probably the last attempt, but it does not appear to overlap the earlier one. The black rubbery stuff pulled off very easily exposing bare concrete. The epoxy pulled off in small pieces and felt soft, but seemed to be on top of slime, not concrete. The four pictures above are a crude panoramic. The one on the far right has a fine vertical crack that we should consider grinding out for an inch or so.

Iron deposits on ladder hardware.

Epoxy delaminating.

below the vertical crack in the panoramic shot. This is why we have rebar. This is harmless.

The valve pit with the 2″ drain marked. The 6″ drain may be controlled by one of the 3 buried valves just behind the photographer.


This shows the 2″ drain hole in the distance, just below the lid, and the electrical conduit that floods the plant when the tank overflows. Sorry for the different perspectives.


When is Olga Water Users Inc. going to sell more memberships?

There is currently a freeze on the sale of new memberships. This will be in place at least until the current round of planning is completed, and we see how the state responds to our plan. We are working very closely with the state engineers to work within their guidelines and suggestions to ensure that we get through the process as efficiently as possible.

Memberships may become available if any are returned to the corporation. (Article VI of the bylaws).

Once we have the plan reviewed by the state DOH and the first steps implemented the board will review if/when more memberships will be made available.

Will there be enough capacity in the future to allow old inactive memberships to be activated?

The short answer is “Yes.”

Here are the estimates for a conservative scenario:

  • OWU now has 162 members, with 120 active with a total of 140 connections (includes counting guest houses as one).
  • At this time no new memberships are being sold.
  • On the high side we estimate 1.5 connections per member.
  • This gives a maximum total of 240 connections.
  • We are planning on (and have seen) 2.5% growth per year
  • after 20 yrs growth we expect 252 connections
  • Max build out:  271 (with more guest homes and bonus max density. May vary with GMA etc)

With our existing water right we would have:                         Average capacity per connection
= (94 acre ft  * (325,850 gal/acre ft) /(365 days/yr))/(240 members)
= 350 gal/day per connection

This is well more than  San Juan County average:
“100 gallons per day/person (average residential occupancy is 2.5, or 250 gallons/residential connection)”

The number of connections allowed will be increased in stages over time.  The initial increases will be based on analysis and minor improvements to the existing system, and eventually having capital improvements in the distant future.

See also:  Where do we Get the Water, and How is it Processed?

Should I activate my membership now to guarantee I have a connection?

No, not unless you also obtain a permit and build a house.

You can activate a membership, install a meter and a spigot and use water, but the Wa state DOH would not count this as a connection to a habitable structure or an ERU. This would also throw out our ability to plan responsible expansion of the water system belonging to (and paid for by) us, the members.

Based on the highest growth rate considered reasonable we have the plans and the capital budget to expand the capacity of Olga Water faster than the demand, if we continue with the current pattern of active member participation in conservation.

More details of the number of tax parcels will be put on this page later.

How many memberships are needed for a given property?

The current bylaws state one membership is needed for each property.

If you have more than one permitted residence on the same tax parcel,
they can share the same membership, although OWU requires that there is a separate
meter on each house to help identify leaks and to gather information on guest houses etc.

Each habitable structure (connection) will count as one ERU towards our system limit of 165.

The fee and rate schedule is structured so that it becomes economical for a member to buy
separate memberships for each house, if too much water is used with several houses on the same property.
This makes it reasonably fair for people with one house vs multiple on the same membership.

Restaurants, B&Bs and all business and home combinations still only need one membership per tax parcel number.
The State Dept of Health guidelines allow some flexibility in the counting of ERUs for different
types of customers, but for our small system one ERU per habitable structure is simple and effective.
All connections are metered, so if a particular business uses more water than a typical residence,
they will have to pay more.

It is the State that sets the limit on the number of habitable structures that are connected to our system.
It is the OWU members who have set up the bylaws to allow multiple connections on the same
property to use the same membership.

A member may have more than one membership on the same tax parcel if they plan to sub divide at some time.
The bylaws allow the board to decide if OWU will buy back a membership, if a member chooses to return it.

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