Tag Archives: tannins

Rainwater Catchment

Late Pollen Season in Seattle


Close-up of a worn, metallic fountain pen nib on a black surface.Pollen season is late for us in Seattle, but it will happen.

Don’t let the continued cool, damp weather fool you. Spring will come and pollen will come with it. Pollen is very fine – approximately 40 microns and decays quickly, causing odor and tannins or discoloration in your stored water. While not harmful to health, it can be unpleasant. You can choose to divert that spring rain from your storage or conduct simple maintenance tasks.

If you have a screen basket in your collection tank, or sump, a 40 micron insert filter works very well as a first line of defense. These filters are from the dairy industry and are FDA approved food grade.

If your system has a vortex filter, be sure to keep the screen clean by light scrubbing as much as needed, this could be every few days depending on amounts.

Keep gutters clean. If gutter screens are left unchecked, accumulation can restrict flow and cause a slime inside of your gutters. When cleaning gutters, be sure to divert away from your cistern or sump.

A sediment filter can be installed between your collection sump tank and storage. Be sure the micron rating is 40 micron or less for best results. You will more than likely need to change this filter often during the season for best results. Keeping your sump tank clean will help extend the life of the filter.

The idea is to send collected rainfall to your storage as free of pollen as possible.

Rainwater Catchment, Rainwater Harvesting Education

What Causes Discoloration in My Water?


A small wooden shed beside a grassy hill with forested mountains in the background.Tannins in drinking water are caused by natural decaying of organic matter. Leaves or pine needles in the gutters are generally the cause in a rainwater collection system. A faint yellowing of water generally occurs at .5 parts per million or PPMs with .5 – 2.0 PPMs looking likethe color of ginger ale, and 3.0 – 5.0 PPMs would take on the appearance of dark tea. The tannins may cause a yellow color of the water, yellow staining on fixtures, and yellow staining in laundry.

Although aesthetically displeasing, tannins generally pose no real health risk, but may affect the performance of the UV system by not allowing the UV light to penetrate thoroughly through the water column.

Therefore, it is very important to minimize tannins before storage of collected rainwater. Organic matter must be kept from accumulating in gutters, down spouts, and screen baskets. Gutter screens are an effective method of prevention of organics in gutters and down spouts. Both gutter screens and screen baskets should be inspected and cleaned as needed to prevent tannins from occurring. Since the discoloration is in solution, removal can be difficult and expensive. Ozone, ion exchange, and activated carbon can help with removal of tannins to some degree. If you do end up with tannins in your water, it is best to drain the cisterns, rinse and start collection again, however the best solution is diligence in maintenance.

Residential Rainwater Collection

Simple Gutter Maintenance Tasks

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A series of large water tanks with connected pipes along a pathway.Asthe weather begins tofeelmore like winter than autumn and our thoughts turn towards family and friends asthe Thanksgiving holiday approaches, don’t neglect your gutter maintenance routine.

No one likes to clean gutters – especially during the holiday season. But, with the winds blowing, this is the most important time of year to be on top of your gutters. Wind blows pine needles and leavesfrom shedding trees – not only into your yard, but into your gutters as well, causing obstructions in the gutters and downspouts. Organic matter, created by tannins in your stored water can be eliminated by removing debris from your gutters and screen baskets. While gutters should be inspected twice permonth and cleaned as necessary to be sure your stored water remains clean and clear, this maintenance practice is most important at this time of year.

Don’t letan accident spoil your holidays. Please remember to take care while on a ladder by following manufacturer’s safety guidelines. To eliminate the need to climb a ladder, gutter screening is the most effective measure of first line screening. Buy good quality gutter screens for highperformance. An extruded framework with stainless steel meshing is desirable.

Don’t forget the screen baskets in either the sump tank or top of cisterns, too. They should be inspected a few times per month and cleaned as needed.

These simple gutter maintenance tasks will help ensure collected water is safe and clean.